crt: Remove __chkstk from libkernel32.a for arm32

This matches what was done for x86_64 in 29284a3727.

On Windows 10 IoT, this symbol apparently isn't available from
kernel32, see
https://github.com/mstorsjo/llvm-mingw/issues/67#issuecomment-593431931
for discussion.

The symbol is available in the compiler-rt builtins library, like
the corresponding ones for all other architectures as well.
Normally, that one is the one included, but if -lkernel32 is
explicitly passed when linking (as is done by e.g. CMake), that one
is searched before the compiler-rt builtins library.

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/lib-common/kernel32.def.in

diff --git a/mingw-w64-crt/lib-common/kernel32.def.in b/mingw-w64-crt/lib-common/kernel32.def.in
index e92f235..4ed3fe0 100644
--- a/mingw-w64-crt/lib-common/kernel32.def.in
+++ b/mingw-w64-crt/lib-common/kernel32.def.in
@@ -1646,7 +1646,9 @@
 ZombifyActCtxWorker
 F_X64(__C_specific_handler)
 F_ARM32(__C_specific_handler)
-F_ARM32(__chkstk)
+; This isn't always available and shouldn't be linked from here, but should
+; be statically linked from the compiler support library.
+;F_ARM32(__chkstk)
 F_X64(__misaligned_access)
 _hread
 _hwrite