Test if errno.h is available for some platforms

[David Friedman]

This one is a bug in the Makefile.

Vincent Richomme wrote:
> For now I have commented everything in d\phobos2\config\errno.x3 and I 
> am getting an other error about not finding gcc/config/fpcls.d:
> 
> make[3]: Entering directory 
> `/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/arm-mingw32ce/libphobos' 
> 
> true "AR_FLAGS=rc" "CC_FOR_BUILD=gcc" 
> "CC_FOR_TARGET=/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/xgcc 
> -B/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/ 
> -B/opt/mingw32ce/arm-mingw32ce/bin/ -B/opt/mingw32ce/arm-mingw32ce/lib/ 
> -isystem /opt/mingw32ce/arm-mingw32ce/include -isystem 
> /opt/mingw32ce/arm-mingw32ce/sys-include" "CFLAGS=-O2 -g -O2 " 
> "CXXFLAGS=-g -O2 " "CFLAGS_FOR_BUILD=-g -O2" "CFLAGS_FOR_TARGET=-O2 -g 
> -O2 " "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 
> 644" "INSTALL_PROGRAM=/usr/bin/install -c" 
> "INSTALL_SCRIPT=/usr/bin/install -c" "LDFLAGS=" "LIBCFLAGS=-O2 -g -O2 " 
> "LIBCFLAGS_FOR_TARGET=-O2 -g -O2 " "MAKE=make" "MAKEINFO=makeinfo 
> --split-size=5000000 --split-size=5000000  " "PICFLAG=" 
> "PICFLAG_FOR_TARGET=" "SHELL=/bin/sh" "RUNTESTFLAGS=" 
> "exec_prefix=/opt/mingw32ce" "infodir=/opt/mingw32ce/info" 
> "libdir=/opt/mingw32ce/lib" "includedir=/opt/mingw32ce/include" 
> "prefix=/opt/mingw32ce" "tooldir=/opt/mingw32ce/arm-mingw32ce" 
> "gdc_include_dir=/opt/mingw32ce/include/d2/4.1.0" "AR=arm-mingw32ce-ar" 
> "AS=/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/as" 
> "LD=/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/collect-ld" 
> "RANLIB=arm-mingw32ce-ranlib" 
> "NM=/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/nm" 
> "NM_FOR_BUILD=" "NM_FOR_TARGET=arm-mingw32ce-nm" "DESTDIR=" "WERROR=" 
> DO=all multi-do # make
> /d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/gdc 
> -B/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/./gcc/ 
> -B/opt/mingw32ce/arm-mingw32ce/bin/ -B/opt/mingw32ce/arm-mingw32ce/lib/ 
> -isystem /opt/mingw32ce/arm-mingw32ce/include -isystem 
> /opt/mingw32ce/arm-mingw32ce/sys-include -o std/boxer.o -g -frelease -O2 
>  -nostdinc -pipe   \
>     -I /d/Professionnel/Projets/cegcc/src/gcc/libphobos -I 
> /d/Professionnel/Projets/cegcc/src/gcc/libphobos/internal/gc -I 
> ./arm-mingw32ce -c 
> /d/Professionnel/Projets/cegcc/src/gcc/libphobos/std/boxer.d
> /d/Professionnel/Projets/cegcc/src/gcc/libphobos/gcc/fpcls.d:19: module 
> fpcls cannot read file 'gcc/config/fpcls.d'
> make[3]: *** [std/boxer.o] Error 1
> make[3]: Leaving directory 
> `/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/arm-mingw32ce/libphobos' 
> 
> make[2]: *** [all] Error 2
> make[2]: Leaving directory 
> `/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc/arm-mingw32ce/libphobos' 
> 
> make[1]: *** [all-target-libphobos] Error 2
> make[1]: Leaving directory 
> `/d/Professionnel/Projets/cegcc/src/build-mingw32ce/gcc'
> make: *** [all] Error 2
> 
>