8079788: Fix broken CL version detection in configure for some Visual Studio configurations

Reviewed-by: tbell, erikj

common/autoconf/generated-configure.sh

@@ -4305,7 +4305,7 @@ VS_SDK_PLATFORM_NAME_2013=
 #CUSTOM_AUTOCONF_INCLUDE
 
 # Do not change or remove the following line, it is needed for consistency checks:
-DATE_WHEN_GENERATED=1527649790
+DATE_WHEN_GENERATED=1527770995
 
 ###############################################################################
 #
@@ -38321,8 +38321,12 @@ $as_echo "$as_me: Rewriting OBJDUMP to \"$new_complete\"" >&6;}
   fi
 
 
-  # Restore old path.
+  # Restore old path, except for the microsoft toolchain, which requires VS_PATH
+  # to remain in place. Otherwise the compiler will not work in some situations
+  # in later configure checks.
+  if test "x$TOOLCHAIN_TYPE" != "xmicrosoft"; then
     PATH="$OLD_PATH"
+  fi
 
   # Restore the flags to the user specified values.
   # This is necessary since AC_PROG_CC defaults CFLAGS to "-g -O2"

common/autoconf/toolchain.m4

@@ -334,8 +334,12 @@ AC_DEFUN_ONCE([TOOLCHAIN_PRE_DETECTION],
 # Restore path, etc
 AC_DEFUN_ONCE([TOOLCHAIN_POST_DETECTION],
 [
-  # Restore old path.
+  # Restore old path, except for the microsoft toolchain, which requires VS_PATH
+  # to remain in place. Otherwise the compiler will not work in some situations
+  # in later configure checks.
+  if test "x$TOOLCHAIN_TYPE" != "xmicrosoft"; then
     PATH="$OLD_PATH"
+  fi
 
   # Restore the flags to the user specified values.
   # This is necessary since AC_PROG_CC defaults CFLAGS to "-g -O2"