From 2c61e9c76a9665ca0f93d6a21a17030fe22b8f1c Mon Sep 17 00:00:00 2001
From: Yang Tse <yangsita@gmail.com>
Date: Fri, 20 Jun 2008 18:09:48 +0000
Subject: Modified configuration script to actually verify if the compiler is
 good enough at detecting compilation errors or at least it has been properly
 configured to do so. Configuration heavily depends on this capability, so if
 this compiler sanity check fails the configuration process will now fail.

---
 acinclude.m4 | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

(limited to 'acinclude.m4')

diff --git a/acinclude.m4 b/acinclude.m4
index 792ceaede..b72604ab7 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -22,6 +22,94 @@
 ###########################################################################
 
 
+dnl CURL_CHECK_COMPILER_HALT_ON_ERROR
+dnl -------------------------------------------------
+dnl Verifies if the compiler actually halts after the
+dnl compilation phase without generating any object
+dnl code file, when the source compiles with errors.
+
+AC_DEFUN([CURL_CHECK_COMPILER_HALT_ON_ERROR], [
+  AC_MSG_CHECKING([if compiler halts on compilation errors])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+    ]],[[
+      force compilation error
+    ]])
+  ],[
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler does not halt on compilation errors.])
+  ],[
+    AC_MSG_RESULT([yes])
+  ])
+])
+
+
+dnl CURL_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE
+dnl -------------------------------------------------
+dnl Verifies if the compiler actually halts after the
+dnl compilation phase without generating any object
+dnl code file, when the source code tries to define a
+dnl type for a constant array with negative dimension.
+
+AC_DEFUN([CURL_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE], [
+  AC_REQUIRE([CURL_CHECK_COMPILER_HALT_ON_ERROR])dnl
+  AC_MSG_CHECKING([if compiler halts on negative sized arrays])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+      typedef char bad_t[sizeof(char) == sizeof(int) ? -1 : -1 ];
+    ]],[[
+      bad_t dummy;
+    ]])
+  ],[
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler does not halt on negative sized arrays.])
+  ],[
+    AC_MSG_RESULT([yes])
+  ])
+])
+
+
+dnl CURL_CHECK_DEF(SYMBOL, [INCLUDES], [SILENT])
+dnl -------------------------------------------------
+dnl Use the C preprocessor to find out if the given object-style symbol
+dnl is defined and get its expansion. This macro will not use default
+dnl includes even if no INCLUDES argument is given. This macro will run
+dnl silently when invoked with three arguments.
+
+AC_DEFUN([CURL_CHECK_DEF], [
+  AS_VAR_PUSHDEF([ac_HaveDef], [curl_cv_have_def_$1])dnl
+  AS_VAR_PUSHDEF([ac_Def], [curl_cv_def_$1])dnl
+  ifelse($3,,[AC_MSG_CHECKING([for preprocessor definition of $1])])
+  tmp_exp=""
+  AC_PREPROC_IFELSE([
+    AC_LANG_SOURCE(
+ifelse($2,,,[$2])[[
+#ifdef $1
+CURL_DEF_TOKEN $1
+#endif
+    ]])
+  ],[
+    tmp_exp=`eval "$ac_cpp conftest.$ac_ext" 2>/dev/null | \
+      "$GREP" CURL_DEF_TOKEN 2>/dev/null | \
+      "$SED" 's/.*CURL_DEF_TOKEN[[ ]]//' 2>/dev/null | \
+      "$SED" 'q' 2>/dev/null`
+    if test "$tmp_exp" = "$1"; then
+      tmp_exp=""
+    fi
+  ])
+  if test -z "$tmp_exp"; then
+    AS_VAR_SET([ac_HaveDef], [no])
+    ifelse($3,,[AC_MSG_RESULT([no])])
+  else
+    AS_VAR_SET([ac_HaveDef], [yes])
+    AS_VAR_SET([ac_Def], [$tmp_exp])
+    ifelse($3,,[AC_MSG_RESULT([$tmp_exp])])
+  fi
+  AS_VAR_POPDEF([ac_Def])dnl
+  AS_VAR_POPDEF([ac_HaveDef])dnl
+])
+
+
 dnl CURL_CHECK_HEADER_WINDOWS
 dnl -------------------------------------------------
 dnl Check for compilable and valid windows.h header 
-- 
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