Test if errno.h is available for some platforms

[Vincent Richomme]

Hi,

when  trying to cross-compile gdc for wince platform I get an error due 
to errno.h (errno.h is not available on mingw32ce).
 From what I see a test is done via a d\phobos2\config\errno.x3.

Could it be possible to check if platform has errno.h before to start a 
test.







ake[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
CC_FOR_BUILD="gcc -I 
/d/Professionnel/Projets/cegcc/src/gcc/libphobos/config" 
BUILD_LIBIBERTY=../../build-i686-pc-cygwin/libiberty/libiberty.a 
/d/Professionnel/Projets/cegcc/src/gcc/libphobos/config/x3 
/d/Professionnel/Projets/cegcc/src/gcc/libphobos/config/errno.x3 -o 
arm-mingw32ce/gcc/config/errno.d 
/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 -DHAVE_CONFIG_H -I . -I 
/d/Professionnel/Projets/cegcc/src/gcc/libphobos/gcc
** x3: running ./errno.x3.exe -o arm-mingw32ce/gcc/config/errno.d 
/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 -DHAVE_CONFIG_H -I . -I 
/d/Professionnel/Projets/cegcc/src/gcc/libphobos/gcc
x3: failed to get macros.
make[3]: *** [arm-mingw32ce/gcc/config/errno.d] 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