crt: Don't initialize lconv to unsigned char mode

Since the initial commit of mingw-w64, there's a call (in a
constructor in crt/charmax.c, pulled in via the mingw_initcharmax
variable) to __lconv_init(), which reconfigures the CRT's lconv
info to unsigned char mode - but there's no explanation for why
this is the case.

The fact that mingw-w64 initializes lconv info this way breaks
a test in llvm's libc++ (where it expects lconv's frac_digits to
be intialized to CHAR_MAX, not UCHAR_MAX). This also differs to
how MSVC environments behave, where they are initialized to
CHAR_MAX.

So unless there's a clear known reason why we'd initialize it
to unsigned char mode, revert to the same behaviour as MSVC has.

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

mingw-w64-crt/crt/crtexe.c

diff --git a/mingw-w64-crt/crt/crtexe.c b/mingw-w64-crt/crt/crtexe.c
index 6460543..4c7830f 100644
--- a/mingw-w64-crt/crt/crtexe.c
+++ b/mingw-w64-crt/crt/crtexe.c
@@ -332,7 +332,6 @@
 extern int mingw_initltsdrot_force;
 extern int mingw_initltsdyn_force;
 extern int mingw_initltssuo_force;
-extern int mingw_initcharmax;
 
 static int __cdecl
 check_managed_app (void)
@@ -346,7 +345,6 @@
   mingw_initltsdrot_force=1;
   mingw_initltsdyn_force=1;
   mingw_initltssuo_force=1;
-  mingw_initcharmax=1;
 
   pDOSHeader = (PIMAGE_DOS_HEADER) &__ImageBase;
   if (pDOSHeader->e_magic != IMAGE_DOS_SIGNATURE)