Add MSVC_DETECT to Makefile

Specifying make MSVC_DETECT=0 ... overrides all of the detection logic for
the Microsoft C Compiler and simply assumes that the environment is
correct. This obviously means that building both 32 and 64-bit CHAINS is
not possible.

checkenv script added which outputs a warning if the environment appears
not to include the Windows SDK, tools or the Microsoft C Runtime. The
script also attempts to determine the architecture of cl.exe and so advise
which CHAINS value can be built with MSVC_DETECT=0. No checking logic
added to Makefile, so specifying CHAINS=msvc64 with an x86 compiler and
vice versa will simply build invalid object files.

Updated CHANGES and also added execute bit to findwinsdk.

.gitattributes

@@ -1,3 +1,4 @@
 * text=auto
 
 findwinsdk text eol=lf
+checkenv text eol=lf

CHANGES

@@ -1,6 +1,8 @@
 Next version
 - Fixes for clang (patch by Roven Gabriel)
-- Improve autodetection of WinSDK paths (patch by David Allsop)
+- Improve autodetection of WinSDK paths (patch by David Allsopp)
+- Add MSVC_DETECT Makefile variable which overrides all C Compiler detection logic when 0.
+- Add checkenv script which determines if the environment is sound specifying MSVC_DETECT=0
 
 Version 0.34
 - New option -norelrelocs to check that no relative flexdll relocations are created (this ensures that the generated DLLs can be loaded at any address),

Makefile

@@ -37,6 +37,16 @@ Makefile.winsdk: findwinsdk
 	bash ./findwinsdk x86 > $@
 	bash ./findwinsdk x64 64 >> $@
 
+MSVC_DETECT=1
+MSVC_FLAGS=/nologo /MD -D_CRT_SECURE_NO_DEPRECATE /GS-
+
+ifeq ($(MSVC_DETECT),0)
+# Assume that the environment is correctly set for a single Microsoft C Compiler; don't attempt to guess anything
+MSVC_PREFIX=
+MSVC64_PREFIX=
+MSVCC=cl.exe $(MSVC_FLAGS)
+MSVCC64=cl.exe $(MSVC_FLAGS)
+else
 ifeq ($(SDK),)
 # Otherwise, assume the 32-bit version of VS 2008 or Win7 SDK is in the path.
 
@@ -50,15 +60,16 @@ MSVC_PREFIX=LIB="$(MSVC_LIB)" INCLUDE="$(MSVC_INCLUDE)"
 MSVC64_LIB = $(MSVC_LIB1)/Lib/amd64;$(MSVC_LIB2)/Lib/x64
 MSVC64_PREFIX=LIB="$(MSVC64_LIB)" INCLUDE="$(MSVC_INCLUDE)" 
 
-MSVCC = $(MSVCC_ROOT)/cl.exe /nologo /MD -D_CRT_SECURE_NO_DEPRECATE /GS-
-MSVCC64 = $(MSVCC_ROOT)/amd64/cl.exe /nologo /MD -D_CRT_SECURE_NO_DEPRECATE /GS-
+MSVCC = $(MSVCC_ROOT)/cl.exe $(MSVC_FLAGS)
+MSVCC64 = $(MSVCC_ROOT)/amd64/cl.exe $(MSVC_FLAGS)
 else
 MSVCC_ROOT:=
 MSVC_PREFIX=PATH="$(SDK):$(PATH)" LIB="$(SDK_LIB);$(LIB)" INCLUDE="$(SDK_INC);$(INCLUDE)" 
 MSVC64_PREFIX=PATH="$(SDK64):$(PATH)" LIB="$(SDK64_LIB);$(LIB)" INCLUDE="$(SDK64_INC);$(INCLUDE)" 
 
-MSVCC = cl.exe /nologo /MD -D_CRT_SECURE_NO_DEPRECATE /GS-
-MSVCC64 = cl.exe /nologo /MD -D_CRT_SECURE_NO_DEPRECATE /GS-
+MSVCC = cl.exe $(MSVC_FLAGS)
+MSVCC64 = cl.exe $(MSVC_FLAGS)
+endif
 endif
 
 show_root:

checkenv

@@ -0,0 +1,55 @@
+#!/bin/bash
+
+# Analyse the environment for Microsoft C Compilers
+
+# Care needed because spaces in directory names are a given
+#   (if only Unix were routinely configured that way...)
+# IFS chosen to be a character illegal in Windows filenames and unlikely in Unix
+SAVE_IFS=$IFS
+
+test ()
+{
+  IFS=*
+  for f in $1; do find "$f" -maxdepth 1 -iname $2 -print -quit; done 2>/dev/null | grep "." -q
+  if [ $? -eq 1 ] ; then
+    echo "Cannot find $3">&2
+    exit 1
+  fi
+  IFS=$SAVE_IFS
+}
+
+# Check for Windows.h in INCLUDE
+test "${INCLUDE//;/*}" windows.h "Windows SDK Headers (Windows.h, etc.)"
+
+# Check for stdlib.h in INCLUDE
+test "${INCLUDE//;/*}" stdlib.h "Microsoft CRT Headers (stdlib.h, etc.)"
+
+# Check for msvcrt.lib in LIB
+test "${LIB//;/*}" msvcrt.lib "Microsoft CRT Libraries (msvcrt.lib, etc.)"
+
+# Check for kernel32.lib in LIB
+test "${LIB//;/*}" kernel32.lib "Windows SDK Libraries (kernel32.lib, etc.)"
+
+# Check for cl.exe in PATH
+test "${PATH//:/*}" cl.exe "Microsoft C Compiler (cl.exe)"
+
+# Check for rc.exe in PATH
+test "${PATH//:/*}" rc.exe "Microsoft Resource Compiler (rc.exe)"
+
+# Check for link.exe in PATH (largely academic - should hit coreutils link if nothing else)
+test "${PATH//:/*}" link.exe "Microsoft Linker (link.exe)"
+
+PROB=
+# Check that link is the Microsoft Linker
+if [ "`link --version | head -1 | fgrep "Microsoft (R) Incremental Linker"`" == "" ] ; then
+  echo "Warning - link does not appear to be the Microsoft Linker, you may need to adjust your PATH"
+  PROB="Probably "
+fi
+
+echo Microsoft C Compiler environment appears to be sound
+if [ -z "`cl /? 2>&1 | head -1 | fgrep x86`" ] ; then
+  CHAINS=msvc64
+else
+  CHAINS=msvc
+fi
+echo ${PROB}OK to build using MSVC_DETECT=0 CHAINS=$CHAINS