+dnl gcc 3.4 has a pch bug which truncates wide character constants in headers.
+dnl Hopefully for a non-unicode build there aren't any wide constants in
+dnl headers, but for a unicode build it's best to disable pch.
+if test "$wxUSE_UNICODE" = yes -a "$GCC" = yes -a "$bk_use_pch" != no
+then
+ AC_CACHE_CHECK(
+ [for gcc precompiled header bug],
+ [wx_cv_gcc_pch_bug],
+ [[
+ echo '#include <stdio.h>
+ const wchar_t test_var[] = L"awidetest";' > conftest.h
+
+ echo '#include "conftest.h"
+ int main()
+ {
+ printf("%ls", test_var);
+ return 0;
+ }' > conftest.cpp
+
+ wx_cv_gcc_pch_bug="pch not supported"
+
+ if $CXX conftest.h >/dev/null 2>&1
+ then
+ wx_cv_gcc_pch_bug=
+
+ if $CXX -o conftest$PROGRAM_EXT conftest.cpp >/dev/null 2>&1
+ then
+ if tr -dc '[a-z]' < conftest$PROGRAM_EXT |
+ grep awidetest >/dev/null
+ then
+ wx_cv_gcc_pch_bug=no
+ else
+ wx_cv_gcc_pch_bug=yes
+ fi
+ fi
+ fi
+
+ rm -f conftest.h conftest.gch conftest.cpp conftest$PROGRAM_EXT
+ ]])
+
+ if test "$wx_cv_gcc_pch_bug" = yes; then
+ dnl make the default for pch 'no'
+ dnl further below check whether the user overrode and warn them
+ bk_use_pch=no
+ fi
+fi
+