--- configure.ac.orig	2025-08-08 14:55:07
+++ configure.ac	2025-08-09 23:20:14
@@ -175,7 +175,7 @@
 #
 
 AM_INIT_AUTOMAKE([subdir-objects serial-tests])
-AC_PREFIX_DEFAULT(/usr/local)
+AC_PREFIX_DEFAULT(/opt/local)
 AC_CONFIG_SRCDIR([src/include/a68g.h])
 AC_CONFIG_HEADERS([a68g-config.h])
 AC_PROG_INSTALL
@@ -199,12 +199,12 @@
 else
 # On rhel8 "rpmbuild" sneaks in -pie and -fPIE, so a68g also needs to pass through.
 # On Suse15 the header files for pgsql and R have their own directories.
-  COPTFLAGS="-g -O2 -Wall -I /usr/include/pgsql -I /usr/lib64/R/include"
-  LDOPTFLAG="-L /usr/lib64/R/lib"
+  COPTFLAGS="-g -O2 -Wall $CPPFLAGS"
+  LDOPTFLAG="$LDFLAGS"
 # from /usr/lib/rpm/redhat/macros
   CFLAGS="${CFLAGS:-$COPTFLAGS}" ; export CFLAGS
   LDFLAGS="${LDFLAGS:-$LDOPTFLAGS}" ; export LDFLAGS
-  A68G_AC_PROG_CC_CFLAGS([--std=c17])
+  A68G_AC_PROG_CC_CFLAGS([-std=c17])
   A68G_AC_PROG_CC_CFLAGS([-Wall])
   A68G_AC_PROG_CC_CFLAGS([-Wshadow])
   A68G_AC_PROG_CC_CFLAGS([-Wunused-variable])
@@ -438,101 +438,20 @@
 else
   AC_MSG_NOTICE([... $prefix/include])
   EXTRA_INCLUDES="-I$prefix/include"
-# Set -I/usr/local/include for *BSD
-  if test "x$bsd_include_dirs" = "xyes"; then
-    AC_MSG_NOTICE([... /usr/local/include])
-    EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/local/include"
-  fi
 fi
 
-
-# Homebrew on macOS
-
-if test -d /opt/homebrew; then
-  AC_MSG_NOTICE([... /opt/homebrew])
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/opt/homebrew/include"
-  CFLAGS="$CFLAGS -I/opt/homebrew/include"
-  CPPFLAGS="$CPPFLAGS -I/opt/homebrew/include"
-  CXXFLAGS="$CXXFLAGS -I/opt/homebrew/include"
-  LDFLAGS="$LDFLAGS -L/opt/homebrew/lib"
-fi
-
-# MacPorts on macOS
+# Prefix should be set by the user.
+# Pass extra flags via env.
 
-if test -d /opt/local; then
-  AC_MSG_NOTICE([... /opt/local])
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/opt/local/include"
-  CFLAGS="$CFLAGS -I/opt/local/include"
-  CPPFLAGS="$CPPFLAGS -I/opt/local/include"
-  CXXFLAGS="$CXXFLAGS -I/opt/local/include"
-  LDFLAGS="$LDFLAGS -L/opt/local/lib"
+if test -d $prefix; then
+  AC_MSG_NOTICE([... $prefix])
+  EXTRA_INCLUDES="$EXTRA_INCLUDES -I$prefix/include"
+  CFLAGS="$CFLAGS -I$prefix/include"
+  CPPFLAGS="$CPPFLAGS -I$prefix/include"
+  CXXFLAGS="$CXXFLAGS -I$prefix/include"
+  LDFLAGS="$LDFLAGS -L$prefix/lib"
 fi
-
-# GSL on OpenBSD
-
-if test -d /usr/local/include/gsl; then
-  AC_MSG_NOTICE([... /usr/local/include/gsl])
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/local/include"
-  CFLAGS="$CFLAGS -I/usr/local/include"
-  CPPFLAGS="$CPPFLAGS -I/usr/local/include"
-  CXXFLAGS="$CXXFLAGS -I/usr/local/include"
-  LDFLAGS="$LDFLAGS -L/usr/local/lib"
-fi
-
-# R on Debian
-# 
-# if test -d /usr/share/R/include; then
-#   AC_MSG_NOTICE([... /usr/share/R/include])
-#   AC_DEFINE(HAVE_USR_SHARE_R_INCLUDE, 1, [Define this if /usr/share/R/include was detected]) 
-#   EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/share/R/include"
-#   CFLAGS="$CFLAGS -I/usr/share/R/include"
-#   CPPFLAGS="$CPPFLAGS -I/usr/share/R/include"
-#   CXXFLAGS="$CXXFLAGS -I/usr/share/R/include"
-#   LDFLAGS="$LDFLAGS -L/usr/share/R/lib"
-# fi
-
-# Postgresql
-
-if test -d /usr/local/pgsql/include; then
-  AC_MSG_NOTICE([... /usr/local/pgsql/include])
-  AC_DEFINE(HAVE_USR_LOCAL_PGSQL_INCLUDE, 1, [Define this if /usr/local/pgsql/include was detected]) 
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/local/pgsql/include"
-  CFLAGS="$CFLAGS -I/usr/local/pgsql/include"
-  CPPFLAGS="$CPPFLAGS -I/usr/local/pgsql/include"
-  CXXFLAGS="$CXXFLAGS -I/usr/local/pgsql/include"
-  LDFLAGS="$LDFLAGS -L/usr/local/pgsql/lib"
-fi
-
-if test -d /usr/pkg/pgsql/include; then
-  AC_MSG_NOTICE([... /usr/pkg/pgsql/include])
-  AC_DEFINE(HAVE_USR_PKG_PGSQL_INCLUDE, 1, [Define this if /usr/pkg/pgsql/include was detected]) 
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/pkg/pgsql/include"
-  CFLAGS="$CFLAGS -I/usr/pkg/pgsql/include"
-  CPPFLAGS="$CPPFLAGS -I/usr/pkg/pgsql/include"
-  CXXFLAGS="$CXXFLAGS -I/usr/pkg/pgsql/include"
-  LDFLAGS="$LDFLAGS -L/usr/pkg/pgsql/lib"
-fi
-
-if test -d /opt/local/pgsql/include; then
-  AC_MSG_NOTICE([... /opt/local/pgsql/include])
-  AC_DEFINE(HAVE_OPT_LOCAL_PGSQL_INCLUDE, 1, [Define this if /opt/local/pgsql/include was detected]) 
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/opt/local/pgsql/include"
-  CFLAGS="$CFLAGS -I/opt/local/pgsql/include"
-  CPPFLAGS="$CPPFLAGS -I/opt/local/pgsql/include"
-  CXXFLAGS="$CXXFLAGS -I/opt/local/pgsql/include"
-  LDFLAGS="$LDFLAGS -L/opt/local/pgsql/lib"
-fi
-
-if test -d /usr/include/postgresql; then
-  AC_MSG_NOTICE([... /usr/include/postgresql])
-  AC_DEFINE(HAVE_USR_INCLUDE_POSTGRESQL, 1, [Define this if /usr/include/postgresql was detected]) 
-  EXTRA_INCLUDES="$EXTRA_INCLUDES -I/usr/include/postgresql"
-  CFLAGS="$CFLAGS -I/usr/include/postgresql"
-  CPPFLAGS="$CPPFLAGS -I/usr/include/postgresql"
-  CXXFLAGS="$CXXFLAGS -I/usr/include/postgresql"
-  LDFLAGS="$LDFLAGS -L/usr/lib"
-fi
-
+ 
 AC_MSG_NOTICE([Extra includes $EXTRA_INCLUDES])
 EXTRA_INCLUDES=m4_strip($EXTRA_INCLUDES)
 AC_MSG_NOTICE([Extra includes $EXTRA_INCLUDES])
