thodg/libgit2

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0e0f296..88eb9ec 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,6 +64,7 @@ OPTION(USE_EXT_HTTP_PARSER		"Use system HTTP_Parser if available"			 ON)
 OPTION(DEBUG_POOL			"Enable debug pool allocator"				OFF)
 OPTION(ENABLE_WERROR			"Enable compilation with -Werror"			OFF)
 OPTION(USE_BUNDLED_ZLIB    		"Use the bundled version of zlib"			OFF)
+OPTION(DEPRECATE_HARD			"Do not include deprecated functions in the library"	OFF)
 
 IF (UNIX AND NOT APPLE)
 	OPTION(ENABLE_REPRODUCIBLE_BUILDS "Enable reproducible builds"				OFF)
@@ -105,8 +106,9 @@ SET(LIBGIT2_VERSION_STRING "${LIBGIT2_VERSION_MAJOR}.${LIBGIT2_VERSION_MINOR}.${
 FILE(STRINGS "${libgit2_SOURCE_DIR}/include/git2/version.h" GIT2_HEADER_SOVERSION REGEX "^#define LIBGIT2_SOVERSION [0-9]+$")
 STRING(REGEX REPLACE "^.*LIBGIT2_SOVERSION ([0-9]+)$" "\\1" LIBGIT2_SOVERSION "${GIT2_HEADER_SOVERSION}")
 
-# Ensure that we do not use deprecated functions internally
-ADD_DEFINITIONS(-DGIT_DEPRECATE_HARD)
+IF (DEPRECATE_HARD)
+	ADD_DEFINITIONS(-DGIT_DEPRECATE_HARD)
+ENDIF()
 
 # Platform specific compilation flags
 IF (MSVC)
diff --git a/README.md b/README.md
index b675fde..3d05dab 100644
--- a/README.md
+++ b/README.md
@@ -4,9 +4,10 @@ libgit2 - the Git linkable library
 | Build Status | |
 | ------------ | - |
 | **master** branch CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=master)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=master)   |
+| **v0.28 branch** CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=maint/v0.28)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=maint/v0.28) |
 | **v0.27 branch** CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=maint/v0.27)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=maint/v0.27) |
 | **v0.26 branch** CI builds | [![Azure Pipelines Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/libgit2?branchName=maint/v0.26)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=7&branchName=maint/v0.26) |
-| **Nightly** builds | [![Azure Pipelines Build Status](https://libgit2.visualstudio.com/libgit2/_apis/build/status/libgit2?branchName=master&label=Full+Build)](https://libgit2.visualstudio.com/libgit2/_build/latest?definitionId=9&branchName=master) [![Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/coverity?branchName=master&label=Coverity+Build)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=21?branchName=master) [![Coverity Scan Build Status](https://scan.coverity.com/projects/639/badge.svg)](https://scan.coverity.com/projects/639) |
+| **Nightly** builds | [![Azure Pipelines Build Status](https://libgit2.visualstudio.com/libgit2/_apis/build/status/nightly?branchName=master&label=Full+Build)](https://libgit2.visualstudio.com/libgit2/_build/latest?definitionId=9&branchName=master) [![Coverity Build Status](https://dev.azure.com/libgit2/libgit2/_apis/build/status/coverity?branchName=master&label=Coverity+Build)](https://dev.azure.com/libgit2/libgit2/_build/latest?definitionId=21?branchName=master) [![Coverity Scan Build Status](https://scan.coverity.com/projects/639/badge.svg)](https://scan.coverity.com/projects/639) |
 
 `libgit2` is a portable, pure C implementation of the Git core methods
 provided as a linkable library with a solid API, allowing to build Git
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index e4931cc..a37319a 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -16,7 +16,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
 
 - job: linux_amd64_trusty_gcc_mbedtls
@@ -29,7 +29,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS
+       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
 
 - job: linux_amd64_trusty_clang_openssl
@@ -42,7 +42,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=clang
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
 
 - job: linux_amd64_trusty_clang_mbedtls
@@ -55,7 +55,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=clang
-       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS
+       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
 
 - job: macos
@@ -71,7 +71,8 @@ jobs:
         TMPDIR: $(Agent.TempDirectory)
         PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
         LEAK_CHECK: leaks
-        CMAKE_OPTIONS: -G Ninja
+        CMAKE_OPTIONS: -G Ninja -DDEPRECATE_HARD=ON
+        SKIP_SSH_TESTS: true
 
 - job: windows_vs_amd64
   displayName: 'Windows (amd64; Visual Studio)'
@@ -80,7 +81,7 @@ jobs:
   - template: azure-pipelines/powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013 Win64"
+        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013 Win64" -DDEPRECATE_HARD=ON
 
 - job: windows_vs_x86
   displayName: 'Windows (x86; Visual Studio)'
@@ -89,7 +90,7 @@ jobs:
   - template: azure-pipelines/powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013"
+        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013" -DDEPRECATE_HARD=ON
 
 - job: windows_mingw_amd64
   displayName: 'Windows (amd64; MinGW)'
@@ -103,7 +104,7 @@ jobs:
   - template: azure-pipelines/powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -G"MinGW Makefiles"
+        CMAKE_OPTIONS: -G"MinGW Makefiles" -DDEPRECATE_HARD=ON
         PATH: $(Agent.TempDirectory)\mingw64\bin;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\CMake\bin
 
 - job: windows_mingw_x86
@@ -119,7 +120,7 @@ jobs:
   - template: azure-pipelines/powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -G"MinGW Makefiles"
+        CMAKE_OPTIONS: -G"MinGW Makefiles" -DDEPRECATE_HARD=ON
         PATH: $(Agent.TempDirectory)\mingw32\bin;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\CMake\bin
 
 - job: documentation
diff --git a/azure-pipelines/nightly.yml b/azure-pipelines/nightly.yml
index 1d34a14..fd76b97 100644
--- a/azure-pipelines/nightly.yml
+++ b/azure-pipelines/nightly.yml
@@ -12,7 +12,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -26,7 +26,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS
+       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -40,7 +40,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=clang
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -54,7 +54,7 @@ jobs:
       imageName: 'libgit2/trusty-amd64:latest'
       environmentVariables: |
        CC=clang
-       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS
+       CMAKE_OPTIONS=-DUSE_HTTPS=mbedTLS -DSHA1_BACKEND=mbedTLS -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -71,8 +71,9 @@ jobs:
         TMPDIR: $(Agent.TempDirectory)
         PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
         LEAK_CHECK: leaks
-        CMAKE_OPTIONS: -G Ninja
+        CMAKE_OPTIONS: -G Ninja -DDEPRECATE_HARD=ON
         RUN_INVASIVE_TESTS: true
+        SKIP_SSH_TESTS: true
 
 - job: windows_vs_amd64
   displayName: 'Windows (amd64; Visual Studio)'
@@ -81,7 +82,7 @@ jobs:
   - template: powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013 Win64"
+        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013 Win64" -DDEPRECATE_HARD=ON
         RUN_INVASIVE_TESTS: true
 
 - job: windows_vs_x86
@@ -91,7 +92,7 @@ jobs:
   - template: powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013"
+        CMAKE_OPTIONS: -DMSVC_CRTDBG=ON -G"Visual Studio 12 2013" -DDEPRECATE_HARD=ON
         RUN_INVASIVE_TESTS: true
 
 - job: windows_mingw_amd64
@@ -106,7 +107,7 @@ jobs:
   - template: powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -G"MinGW Makefiles"
+        CMAKE_OPTIONS: -G"MinGW Makefiles" -DDEPRECATE_HARD=ON
         PATH: $(Agent.TempDirectory)\mingw64\bin;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\CMake\bin
         RUN_INVASIVE_TESTS: true
 
@@ -123,7 +124,7 @@ jobs:
   - template: powershell.yml
     parameters:
       environmentVariables:
-        CMAKE_OPTIONS: -G"MinGW Makefiles"
+        CMAKE_OPTIONS: -G"MinGW Makefiles" -DDEPRECATE_HARD=ON
         PATH: $(Agent.TempDirectory)\mingw32\bin;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\CMake\bin
         RUN_INVASIVE_TESTS: true
 
@@ -138,7 +139,7 @@ jobs:
       imageName: 'libgit2/bionic-x86:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -153,7 +154,7 @@ jobs:
       imageName: 'libgit2/bionic-x86:latest'
       environmentVariables: |
        CC=clang
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        LEAK_CHECK=valgrind
        RUN_INVASIVE_TESTS=true
 
@@ -168,7 +169,7 @@ jobs:
       imageName: 'libgit2/bionic-arm32:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        RUN_INVASIVE_TESTS=true
        SKIP_PROXY_TESTS=true
 
@@ -183,6 +184,6 @@ jobs:
       imageName: 'libgit2/bionic-arm64:latest'
       environmentVariables: |
        CC=gcc
-       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL
+       CMAKE_OPTIONS=-DUSE_HTTPS=OpenSSL -DDEPRECATE_HARD=ON
        RUN_INVASIVE_TESTS=true
        SKIP_PROXY_TESTS=true
diff --git a/ci/build.sh b/ci/build.sh
index 49e7330..7ffa610 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -16,8 +16,20 @@ indent() { sed "s/^/    /"; }
 echo "Source directory: ${SOURCE_DIR}"
 echo "Build directory:  ${BUILD_DIR}"
 echo ""
-echo "Operating system version:"
+
+if [ "$(uname -s)" = "Darwin" ]; then
+	echo "macOS version:"
+	sw_vers | indent
+fi
+
+if [ -f "/etc/debian_version" ]; then
+	echo "Debian version:"
+	lsb_release -a | indent
+fi
+
+echo "Kernel version:"
 uname -a 2>&1 | indent
+
 echo "CMake version:"
 cmake --version 2>&1 | indent
 echo "Compiler version:"
diff --git a/docs/changelog.md b/docs/changelog.md
index 666eecd..7d1dac6 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,3 +1,13 @@
+v0.28.1
+-------
+
+This is a bugfix release with the following change:
+
+* The deprecated functions (`git_buf_free` and the `giterr_` family of
+  functions) are now exported properly.  In the v0.28 release, they were
+  not given the correct external attributes and they did not have the
+  correct linkage visibility in the v0.28 library.
+
 v0.28
 -----
 
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 49edaec..e631b96 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -5,6 +5,9 @@ FILE(GLOB_RECURSE SRC_EXAMPLE_GIT2 network/*.c network/*.h common.?)
 ADD_EXECUTABLE(cgit2 ${SRC_EXAMPLE_GIT2})
 SET_TARGET_PROPERTIES(cgit2 PROPERTIES C_STANDARD 90)
 
+# Ensure that we do not use deprecated functions internally
+ADD_DEFINITIONS(-DGIT_DEPRECATE_HARD)
+
 IF(WIN32 OR ANDROID)
 	TARGET_LINK_LIBRARIES(cgit2 git2)
 ELSE()
diff --git a/include/git2/version.h b/include/git2/version.h
index 148808c..7b71220 100644
--- a/include/git2/version.h
+++ b/include/git2/version.h
@@ -7,10 +7,10 @@
 #ifndef INCLUDE_git_version_h__
 #define INCLUDE_git_version_h__
 
-#define LIBGIT2_VERSION "0.28.0"
+#define LIBGIT2_VERSION "0.28.1"
 #define LIBGIT2_VER_MAJOR 0
 #define LIBGIT2_VER_MINOR 28
-#define LIBGIT2_VER_REVISION 0
+#define LIBGIT2_VER_REVISION 1
 #define LIBGIT2_VER_PATCH 0
 
 #define LIBGIT2_SOVERSION 28
diff --git a/src/common.h b/src/common.h
index 6e1eac8..18ba72d 100644
--- a/src/common.h
+++ b/src/common.h
@@ -79,6 +79,12 @@
 #include "thread-utils.h"
 #include "integer.h"
 
+/*
+ * Include the declarations for deprecated functions; this ensures
+ * that they're decorated with the proper extern/visibility attributes.
+ */
+#include "git2/deprecated.h"
+
 #include <regex.h>
 
 #define DEFAULT_BUFSIZE 65536
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 6ce5ae0..aaa8ed1 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -11,6 +11,9 @@ ADD_DEFINITIONS(-DCLAR_FIXTURE_PATH=\"${CLAR_FIXTURES}\")
 ADD_DEFINITIONS(-DCLAR_TMPDIR=\"libgit2_tests\")
 ADD_DEFINITIONS(-D_FILE_OFFSET_BITS=64)
 
+# Ensure that we do not use deprecated functions internally
+ADD_DEFINITIONS(-DGIT_DEPRECATE_HARD)
+
 INCLUDE_DIRECTORIES(${CLAR_PATH} ${libgit2_BINARY_DIR}/src)
 FILE(GLOB_RECURSE SRC_TEST ${CLAR_PATH}/*/*.c ${CLAR_PATH}/*/*.h)
 SET(SRC_CLAR "main.c" "clar_libgit2.c" "clar_libgit2_trace.c" "clar_libgit2_timer.c" "clar.c")