improve autoconf

packages/gecode/configure.in

@@ -1,21 +1,24 @@
 dnl Gecode support
 
-AC_ARG_ENABLE(gecode,
-	[ --enable-gecode            install gecode library],
-        [use_gecode="$enableval"], use_gecode=no)
-
-dnl gecode is usually in /usr/local
-if test -d /usr/local/include/gecode -a x$SYSROOT = x; then
-  CFLAGS="$CFLAGS -I/usr/local/include"
-  SHLIB_CXXFLAGS="$SHLIB_CXXFLAGS -I/usr/local/include"
-  GECODE_EXTRALIBS="-L/usr/local/lib"
-fi
+AC_ARG_WITH(gecode,
+	[ --with-gecode            install gecode library],
+        [use_gecode="$withval"], use_gecode=no)
 
 if test "$use_gecode" = no; then
   PKG_GECODE=""
 else
   PKG_GECODE="packages/gecode"
+if test -d "$use_gecode"; then
+  CPPFLAGS="$CPPFLAGS -I $use_gecode/include"
+  GECODE_EXTRALIBS="-L $use_gecode/lib"
+     GECODE_PATH="$use_gecode/bin"
+dnl gecode is usually in /usr/local
+elif test -d /usr/local/include/gecode -a x$SYSROOT = x; then
+  CPPFLAGS="$CPPFLAGS -I/usr/local/include"
+  GECODE_EXTRALIBS="-L/usr/local/lib"
 fi
+fi
+
 AC_SUBST(PKG_GECODE)
 
 AC_MSG_CHECKING([if dynamic arrays are supported])
@@ -32,7 +35,7 @@ AC_COMPILE_IFELSE([
 GECODE_VERSION=unknown-gecode-version
 
 
-if test "$use_gecode" = yes; then
+if test "$use_gecode" != no; then
    if test $i_am_cross_compiling = yes
    then
      GECODE_VERSION=4.2.1
@@ -42,9 +45,12 @@ if test "$use_gecode" = yes; then
      else
        GECODE_ARCH=i386
      fi
-     GECODE_PATH=`which fzn-gecode`
-     GECODE_PATH=`dirname "$GECODE_PATH"`
+     if test "$use_gecode" = yes; then
+       GECODE_PATH=`which fzn-gecode`
      GECODE_PATH=`dirname "$GECODE_PATH"`
+     else
+       GECODE_PATH="$use_gecode"
+     fi
      GECODE_INCLUDES="$GECODE_PATH"/include
      GECODE_LIBDIR="\"$GECODE_PATH\""/lib
      GECODE_BINDIR="\"$GECODE_PATH\""/bin
@@ -76,6 +82,7 @@ if test "$use_gecode" = yes; then
    [AC_MSG_ERROR([cannot determine gecode version])])
    case "$target_os" in
      *darwin*)
+     if test "$use_gecode" = yes; then
      AC_MSG_CHECKING([if -framework gecode is required])
      AC_LANG_PUSH([C++])
      saved_CXXFLAGS="$CXXFLAGS"
@@ -90,6 +97,7 @@ return 0;
      [AC_MSG_RESULT([no])])
      AC_LANG_POP()
      CXXFLAGS="$saved_CXXFLAGS"
+     fi
      ;;
    esac