Revert "Do use -O1 for Apple Clang older than 9.1.0"

This reverts commit 55b9706b, which is obsoleted
by b4f666f2 "Bump Xcode baseline to 9.3".

Change-Id: Id2240351ed9495e311d55887b8e34f2aa776ae06
Reviewed-on: https://gerrit.libreoffice.org/63896
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

config_host.mk.in

@@ -62,7 +62,6 @@ export CDR_LIBS=$(gb_SPACE)@CDR_LIBS@
 @x_CFLAGS@ export CFLAGS=@CFLAGS@
 export CLANGDIR=@CLANGDIR@
 export CLANGLIBDIR=@CLANGLIBDIR@
-export CLANGVER=@CLANGVER@
 export CLUCENE_CFLAGS=$(gb_SPACE)@CLUCENE_CFLAGS@
 export CLUCENE_LIBS=$(gb_SPACE)@CLUCENE_LIBS@
 export LIBCMIS_CFLAGS=$(gb_SPACE)@LIBCMIS_CFLAGS@

configure.ac

@@ -3667,7 +3667,6 @@ if test "$COM_IS_CLANG" = TRUE; then
     AC_DEFINE_UNQUOTED(CLANG_FULL_VERSION,$CLANG_FULL_VERSION)
 fi
 AC_SUBST(COM_IS_CLANG)
-AC_SUBST(CLANGVER)
 
 SHOWINCLUDES_PREFIX=
 if test "$_os" = WINNT; then

solenv/gbuild/platform/macosx.mk

@@ -19,10 +19,6 @@
 
 gb_SDKDIR := $(MACOSX_SDK_PATH)
 
-ifeq (PRE_9_1_0,$(shell test $(CLANGVER) -lt 90100 && echo PRE_9_1_0))
-gb_COMPILEROPTFLAGS := -O1
-endif
-
 include $(GBUILDDIR)/platform/com_GCC_defs.mk
 
 # Darwin mktemp -t expects a prefix, not a pattern