cmake: Don't link directly against a libpthread on Android (thanks, Anthony!). Android has pthreads, but it's just part of their C runtime instead of a separate library like the usual Linux platforms. Fixes Bugzilla #3675.
diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
index 15834f5..4ce64c2 100644
--- a/cmake/sdlchecks.cmake
+++ b/cmake/sdlchecks.cmake
@@ -856,7 +856,10 @@ endmacro()
# PTHREAD_LIBS
macro(CheckPTHREAD)
if(PTHREADS)
- if(LINUX)
+ if(ANDROID)
+ # the android libc provides built-in support for pthreads, so no
+ # additional linking or compile flags are necessary
+ elseif(LINUX)
set(PTHREAD_CFLAGS "-D_REENTRANT")
set(PTHREAD_LDFLAGS "-pthread")
elseif(ANDROID)