From 18d508793abbfc4045af7c7c91f6d71bb5bb7ef1 Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Wed, 4 Aug 2021 19:31:36 -0400
Subject: [PATCH 10/12] configure.ac: don't manually search for compiler
 names/flags.

The AC_PROG_CXX macro is generally capable of finding the best C++
compiler on the system these days, including the flags it needs.  This
commit removes the hard-coded list of C++ compilers, and the manual
computation of REQ_CXXFLAGS based on the name of the compiler.

This serves another purpose: the qd-config program is capable of
outputting an appropriate "-I" flag to allow consumers to use libqd
when it is installed in a nonstandard location. At the moment, however,
that "-I" flag is accompanied by whatever other REQ_CXXFLAGS were
computed -- and many of those flags are invalid in the other context.
By eliminating REQ_CXXFLAGS, we solve that problem too.
---
 configure.ac | 43 +------------------------------------------
 1 file changed, 1 insertion(+), 42 deletions(-)

diff --git a/configure.ac b/configure.ac
index a657e8f..5ac7079 100644
--- a/configure.ac
+++ b/configure.ac
@@ -73,51 +73,10 @@ AC_MSG_RESULT($enable_warnings)
 
 # Checks for programs.
 AC_LANG(C++)
-
-# Set up compiler search list.  DUe to possible case insensitive filesystems, 
-# Cygwin and Apple systems sometimes gets confused between cc and CC.
-# Try to use vendor compilers first, as they are often the fastest.
-case $host in 
-  *cygwin* | *mingw* ) cxx_list="" ;;
-  *apple* ) cxx_list="xlC_r xlC icpc pathCC c++ g++ gpp" ;;
-  * ) cxx_list="xlC_r xlC icpc pathCC pgCC cxx aCC CC cc++ FCC KCC RCC c++ g++ gpp" ;;
-esac
-
-AC_PROG_CXX($cxx_list)
+AC_PROG_CXX
 AC_PROG_CC
 
 
-CXX_PROG_NAME=`basename $CXX`
-case $host in
-  powerpc*-*-*)
-    case "$CXX_PROG_NAME" in
-      xlC*) 
-        REQ_CXXFLAGS="$REQ_CXXFLAGS -qstrict"
-      ;;
-    esac
-  ;;
-  i?86-*-* | k?*-*-* | athlon-*-* | ia64-*-* | x86_64-*-*)
-    case "$CXX_PROG_NAME" in
-      icc|icpc|ecc)
-        REQ_CXXFLAGS="$REQ_CXXFLAGS -mp"
-        if test "$enable_warnings" = "yes"; then
-          CXXFLAGS="$CXXFLAGS -wd1572 -wd981 -wd1418 -wd1419"
-        fi
-      ;;
-    esac
-  ;;
-  alpha*-*-*)
-    case "$CXX_PROG_NAME" in
-      cxx) 
-        CXXFLAGS="$CXXFLAGS -std strict_ansi -tweak"
-      ;;
-    esac
-  ;;
-esac
-
-AC_SUBST(REQ_CXXFLAGS)
-CXXFLAGS="$CXXFLAGS $REQ_CXXFLAGS"
-
 if test "$enable_warnings" = "yes"; then
   if test "$GCC" = "yes"; then
     CXXFLAGS="$CXXFLAGS -Wall"
-- 
2.31.1