Remove traces of support for Sun Studio compiler

Per discussion, this compiler suite is no longer maintained, and
it has not been able to compile PostgreSQL since at least PostgreSQL
17.

This removes all the remaining support code for this compiler.

Note that the Solaris operating system continues to be supported, but
using GCC as the compiler.

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/a0f817ee-fb86-483a-8a14-b6f7f5991b6e%40eisentraut.org

configure.ac

@@ -95,12 +95,6 @@ AC_MSG_RESULT([$template])
 PORTNAME=$template
 AC_SUBST(PORTNAME)
 
-# Initialize default assumption that we do not need separate assembly code
-# for TAS (test-and-set).  This can be overridden by the template file
-# when it's executed.
-need_tas=no
-tas_file=dummy.s
-
 # Default, works for most platforms, override in template file if needed
 DLSUFFIX=".so"
 
@@ -400,14 +394,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [@%:@ifndef __INTEL_COMPILER
 choke me
 @%:@endif])], [ICC=yes], [ICC=no])
 
-# Check if it's Sun Studio compiler. We assume that
-# __SUNPRO_C will be defined for Sun Studio compilers
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [@%:@ifndef __SUNPRO_C
-choke me
-@%:@endif])], [SUN_STUDIO_CC=yes], [SUN_STUDIO_CC=no])
-
-AC_SUBST(SUN_STUDIO_CC)
-
 
 #
 # LLVM
@@ -618,7 +604,7 @@ fi
 # __attribute__((visibility("hidden"))) is supported, if we encounter a
 # compiler that supports one of the supported variants of -fvisibility=hidden
 # but uses a different syntax to mark a symbol as exported.
-if test "$GCC" = yes -o "$SUN_STUDIO_CC" = yes ; then
+if test "$GCC" = yes; then
   PGAC_PROG_CC_VAR_OPT(CFLAGS_SL_MODULE, [-fvisibility=hidden])
   # For C++ we additionally want -fvisibility-inlines-hidden
   PGAC_PROG_VARCXX_VARFLAGS_OPT(CXX, CXXFLAGS_SL_MODULE, [-fvisibility=hidden])
@@ -774,19 +760,6 @@ AC_PROG_CPP
 AC_SUBST(GCC)
 
 
-#
-# Set up TAS assembly code if needed; the template file has now had its
-# chance to request this.
-#
-AC_CONFIG_LINKS([src/backend/port/tas.s:src/backend/port/tas/${tas_file}])
-
-if test "$need_tas" = yes ; then
-  TAS=tas.o
-else
-  TAS=""
-fi
-AC_SUBST(TAS)
-
 AC_SUBST(DLSUFFIX)dnl
 AC_DEFINE_UNQUOTED([DLSUFFIX], ["$DLSUFFIX"],
                    [Define to the file name extension of dynamically-loadable modules.])
@@ -2478,8 +2451,6 @@ AC_SUBST(LDFLAGS_EX_BE)
 if test x"$GCC" = x"yes" ; then
   cc_string=`${CC} --version | sed q`
   case $cc_string in [[A-Za-z]]*) ;; *) cc_string="GCC $cc_string";; esac
-elif test x"$SUN_STUDIO_CC" = x"yes" ; then
-  cc_string=`${CC} -V 2>&1 | sed q`
 else
   cc_string=$CC
 fi