Fix Solaris cc wrappers (re: 4e67234)

The versions from the Solaris patch require $CC_EXPLICIT to be set,
which is specific to the internal Solaris build environment.

src/cmd/INIT/cc.sol11.*:
- Cope without $CC_EXPLICIT set in environment; fall back to $CC
  and if that is not set either, detect whether to use cc or gcc.
- Set appropriate flags for cc (Solaris Studio) or gcc, including
  the necessary -D_XPG6 flag, without which ksh crashes on Solaris.

bin/package, src/cmd/INIT/package.sh:
- Update hack to add the -D_XPG6 flag so it applies to gcc only
  (note: the src/cmd/INIT/cc.* scripts are never used for gcc).

bin/package

@@ -5442,12 +5442,12 @@ make|view)
 		esac
 		;;
 	esac
-	# Hack for Solaris 11.4, which needs -D_XPG6 in C flags to not segfault
+	# Hack for Solaris gcc, which needs -D_XPG6 in C flags to not segfault
 	case `uname` in
-	SunOS)	case " $CCFLAGS " in
+	SunOS)	case "$CC, $CCFLAGS " in
 		*" -D_XPG6 "*)
 			;;
-		*)	CCFLAGS="-D_XPG6${CCFLAGS:+ $CCFLAGS}"
+		*gcc,*)	CCFLAGS="-D_XPG6${CCFLAGS:+ $CCFLAGS}"
 			export CCFLAGS
 			;;
 		esac

src/cmd/INIT/cc.sol11.i386

@@ -1,9 +1,16 @@
-: solaris.i386 cc wrapper for reasonable ansi C defaults and 32 bit : 2012-05-18 :
+: solaris.i386 cc wrapper for reasonable ansi C defaults and 32 bit : 2021-01-16 :
 
 HOSTTYPE=sol11.i386
 
 case " $* " in
 *" -dumpmachine "*) echo $HOSTTYPE; exit ;;
 esac
 
+# Solaris build scripts set $CC_EXPLICIT. If not set, function without it.
+case ${CC_EXPLICIT:=$CC} in
+'' | cc)
+	PATH=`/usr/bin/getconf PATH`  # avoid infinite recursion executing 'cc'
+	CC_EXPLICIT=cc
+esac
+
 $CC_EXPLICIT -m32 -xc99 -D_XPG6 "$@"

src/cmd/INIT/cc.sol11.i386-64

@@ -1,9 +1,16 @@
-: solaris.i386-64 cc wrapper for reasonable ansi C defaults and 64 bit : 2012-05-18 :
+: solaris.i386-64 cc wrapper for reasonable ansi C defaults and 64 bit : 2021-01-16 :
 
 HOSTTYPE=sol11.i386-64
 
 case " $* " in
 *" -dumpmachine "*) echo $HOSTTYPE; exit ;;
 esac
 
+# Solaris build scripts set $CC_EXPLICIT. If not set, function without it.
+case ${CC_EXPLICIT:=$CC} in
+'' | cc)
+	PATH=`/usr/bin/getconf PATH`  # avoid infinite recursion executing 'cc'
+	CC_EXPLICIT=cc
+esac
+
 $CC_EXPLICIT -m64 -xc99 -D_XPG6 "$@"

src/cmd/INIT/cc.sol11.sparc

@@ -1,9 +1,16 @@
-: solaris.sparc cc wrapper for reasonable ansi C defaults and 32 bit : 2012-05-18 :
+: solaris.sparc cc wrapper for reasonable ansi C defaults and 32 bit : 2021-01-16 :
 
 HOSTTYPE=sol11.sparc
 
 case " $* " in
 *" -dumpmachine "*) echo $HOSTTYPE; exit ;;
 esac
 
+# Solaris build scripts set $CC_EXPLICIT. If not set, function without it.
+case ${CC_EXPLICIT:=$CC} in
+'' | cc)
+	PATH=`/usr/bin/getconf PATH`  # avoid infinite recursion executing 'cc'
+	CC_EXPLICIT=cc
+esac
+
 $CC_EXPLICIT -m32 -xc99 -D_XPG6 "$@"

src/cmd/INIT/cc.sol11.sparc-64

@@ -1,9 +1,16 @@
-: solaris.sparc-64 cc wrapper for reasonable ansi C defaults and 64 bit : 2012-05-18 :
+: solaris.sparc-64 cc wrapper for reasonable ansi C defaults and 64 bit : 2021-01-16 :
 
 HOSTTYPE=sol11.sparc-64
 
 case " $* " in
 *" -dumpmachine "*) echo $HOSTTYPE; exit ;;
 esac
 
+# Solaris build scripts set $CC_EXPLICIT. If not set, function without it.
+case ${CC_EXPLICIT:=$CC} in
+'' | cc)
+	PATH=`/usr/bin/getconf PATH`  # avoid infinite recursion executing 'cc'
+	CC_EXPLICIT=cc
+esac
+
 $CC_EXPLICIT -m64 -xc99 -D_XPG6 "$@"

src/cmd/INIT/package.sh

@@ -5441,12 +5441,12 @@ make|view)
 		esac
 		;;
 	esac
-	# Hack for Solaris 11.4, which needs -D_XPG6 in C flags to not segfault
+	# Hack for Solaris gcc, which needs -D_XPG6 in C flags to not segfault
 	case `uname` in
-	SunOS)	case " $CCFLAGS " in
+	SunOS)	case "$CC, $CCFLAGS " in
 		*" -D_XPG6 "*)
 			;;
-		*)	CCFLAGS="-D_XPG6${CCFLAGS:+ $CCFLAGS}"
+		*gcc,*)	CCFLAGS="-D_XPG6${CCFLAGS:+ $CCFLAGS}"
 			export CCFLAGS
 			;;
 		esac