Update libffi.pc.in

use -L${toolexeclibdir} instead of -L${libdir}
to be consistent with Makefile.am
Fix build failure when using clang for Android

clang for Android generates __gnu_linux__ define, but gcc for Android doesn't.  So we should add check it for Android
When the function called by the ffi called a function defined in a shared library generate a fatal error
The correction was to take into consideration the GOT.
Darwin/AArch64: Inhibit Clang previous prototype warnings
Darwin/ARM: Inhibit Clang previous prototype warnings
Darwin/i386: Inhibit Clang previous prototype warnings
Darwin/ARM: Assert on NULL dereference

This inhibits an analyzer warning by Clang on all platforms.
Darwin/iOS: Fix mis-typing of vfp_reg_free
Fix dlmalloc warnings due to set_segment_flags, sizeof(size_t)
Darwin/iOS: Improve unified syntax use for LLVM
Darwin: Merge build scripts, redo project, incl. arm64
Darwin/x86_64: Fix 64-bit type shortening warnings
Darwin/aarch64: Fix invalid reference in assembly
Darwin/aarch64: Use CNAME, restrict .size like ARM
Darwin/aarch64: Account for long double being equal to double
Darwin/aarch64: Use Clang cache invalidation builtin
Darwin/aarch64: Fix "shadows declaration" warnings
Darwin/aarch64: Fix size_t assumptions
Darwin/aarch64: Respect iOS ABI re: stack argument alignment
AArch64: Remove duplicitous element_count call.

This inhibits an analyzer warning by Clang.