[AD] Autodetection of constructor attribute support

[Michael Bukin <M.A.Bukin@xxxxxxxxxx>]

This patch adds autodetection of __attribute__((constructor)) support
into configure script.  Constructor functions can be disabled with
--disable-constructor option of configure script.

diff -ruN old/allegro-3.9.30/acconfig.h new/allegro-3.9.30/acconfig.h
--- old/allegro-3.9.30/acconfig.h	Mon Dec 20 06:39:26 1999
+++ new/allegro-3.9.30/acconfig.h	Sun Jan 23 15:26:21 2000
@@ -67,3 +67,6 @@
 /* Define to (void *)-1, if MAP_FAILED is not defined.  */
 #undef MAP_FAILED
 
+/* Define if constructor attribute is supported. */
+#undef ALLEGRO_USE_CONSTRUCTOR
+
diff -ruN old/allegro-3.9.30/aclocal.m4 new/allegro-3.9.30/aclocal.m4
--- old/allegro-3.9.30/aclocal.m4	Mon Dec 20 06:39:26 1999
+++ new/allegro-3.9.30/aclocal.m4	Sun Jan 23 15:30:01 2000
@@ -243,3 +243,30 @@
 fi
 ])
 
+dnl
+dnl Test for constructor attribute support.
+dnl
+dnl Variables:
+dnl  allegro_support_constructor=(yes|no)
+dnl
+AC_DEFUN(ALLEGRO_ACTEST_CONSTRUCTOR,
+[AC_MGS_CHECKING(for constructor attribute)
+AC_ARG_ENABLE(constructor,
+[  --enable-constructor[=x]    enable the use of constructor attr [default=yes]],
+test "X$enableval" != "Xno" && allegro_enable_constructor=yes,
+allegro_enable_constructor=yes)
+
+if test -n "$allegro_enable_constructor"; then
+  AC_TRY_RUN([static int notsupported = 1;
+    void test_ctor (void) __attribute__ ((constructor));
+    void test_ctor (void) { notsupported = 0; }
+    int main (void) { return (notsupported); }],
+  allegro_support_constructor=yes,
+  allegro_support_constructor=no,
+  allegro_support_constructor=no)
+else
+  allegro_support_constructor=no
+fi
+
+AC_MSG_RESULT($allegro_support_constructor)])
+
diff -ruN old/allegro-3.9.30/configure.in new/allegro-3.9.30/configure.in
--- old/allegro-3.9.30/configure.in	Mon Dec 20 06:39:26 1999
+++ new/allegro-3.9.30/configure.in	Sun Jan 23 15:22:19 2000
@@ -131,6 +131,12 @@
   AC_DEFINE(ALLEGRO_LITTLE_ENDIAN)
 fi
 
+dnl Test for constructor attribute support.
+ALLEGRO_ACTEST_CONSTRUCTOR
+if test "X$allegro_support_constructor" = "Xyes"; then
+  AC_DEFINE(ALLEGRO_USE_CONSTRUCTOR)
+fi
+
 dnl How to compile C and asm files.
 if test -n "GCC"; then
   if test "X$allegro_strict_warnings" = "Xyes"; then
diff -ruN old/allegro-3.9.30/include/allegro/alconfig.h new/allegro-3.9.30/include/allegro/alconfig.h
--- old/allegro-3.9.30/include/allegro/alconfig.h	Mon Dec 20 06:39:28 1999
+++ new/allegro-3.9.30/include/allegro/alconfig.h	Sun Jan 23 15:30:29 2000
@@ -55,8 +55,6 @@
 
    #define AL_PRINTFUNC(type, name, args, a, b)    AL_FUNC(type, name, args) __attribute__ ((format (printf, a, b)))
 
-   #define CONSTRUCTOR_FUNCTION(func)              func __attribute__ ((constructor))
-
    #define INLINE          inline
 
    #ifndef ZERO_SIZE
@@ -68,6 +66,12 @@
    #ifdef __i386__
       #define ALLEGRO_I386
    #endif
+#endif
+
+
+/* use constructor functions, if supported */
+#ifdef ALLEGRO_USE_CONSTRUCTOR
+   #define CONSTRUCTOR_FUNCTION(func)              func __attribute__ ((constructor))
 #endif
 
 


-- 
Michael Bukin