diff --git a/acinclude.m4 b/acinclude.m4
new file mode 100644
index 0000000..3d772c7
--- /dev/null
+++ b/acinclude.m4
@@ -0,0 +1,149 @@
+
+dnl **********************************************************************
+dnl CURL_DETECT_ICC ([ACTION-IF-YES])
+dnl
+dnl check if this is the Intel ICC compiler, and if so run the ACTION-IF-YES
+dnl sets the $ICC variable to "yes" or "no"
+dnl **********************************************************************
+AC_DEFUN([CURL_DETECT_ICC],
+[
+    ICC="no"
+    AC_MSG_CHECKING([for icc in use])
+    if test "$GCC" = "yes"; then
+       dnl check if this is icc acting as gcc in disguise
+       AC_EGREP_CPP([^__INTEL_COMPILER], [__INTEL_COMPILER],
+         dnl action if the text is found, this it has not been replaced by the
+         dnl cpp
+         ICC="no",
+         dnl the text was not found, it was replaced by the cpp
+         ICC="yes"
+         AC_MSG_RESULT([yes])
+         [$1]
+       )
+    fi
+    if test "$ICC" = "no"; then
+        # this is not ICC
+        AC_MSG_RESULT([no])
+    fi
+])
+
+dnl We create a function for detecting which compiler we use and then set as
+dnl pendantic compiler options as possible for that particular compiler. The
+dnl options are only used for debug-builds.
+
+AC_DEFUN([CURL_CC_DEBUG_OPTS],
+[
+    if test "z$ICC" = "z"; then
+      CURL_DETECT_ICC
+    fi
+
+    if test "$GCC" = "yes"; then
+
+       dnl figure out gcc version!
+       AC_MSG_CHECKING([gcc version])
+       gccver=`$CC -dumpversion`
+       num1=`echo $gccver | cut -d . -f1`
+       num2=`echo $gccver | cut -d . -f2`
+       gccnum=`(expr $num1 "*" 100 + $num2) 2>/dev/null`
+       AC_MSG_RESULT($gccver)
+
+       if test "$ICC" = "yes"; then
+         dnl this is icc, not gcc.
+
+         dnl ICC warnings we ignore:
+         dnl * 269 warns on our "%Od" printf formatters for curl_off_t output:
+         dnl   "invalid format string conversion"
+         dnl * 279 warns on static conditions in while expressions
+         dnl * 981 warns on "operands are evaluated in unspecified order"
+         dnl * 1418 "external definition with no prior declaration"
+         dnl * 1419 warns on "external declaration in primary source file"
+         dnl   which we know and do on purpose.
+
+         WARN="-wd279,269,981,1418,1419"
+
+         if test "$gccnum" -gt "600"; then
+            dnl icc 6.0 and older doesn't have the -Wall flag
+            WARN="-Wall $WARN"
+         fi
+       else dnl $ICC = yes
+         dnl this is a set of options we believe *ALL* gcc versions support:
+         WARN="-W -Wall -Wwrite-strings -pedantic -Wpointer-arith -Wnested-externs -Winline -Wmissing-prototypes"
+
+         dnl -Wcast-align is a bit too annoying on all gcc versions ;-)
+
+         if test "$gccnum" -ge "207"; then
+           dnl gcc 2.7 or later
+           WARN="$WARN -Wmissing-declarations"
+         fi
+
+         if test "$gccnum" -gt "295"; then
+           dnl only if the compiler is newer than 2.95 since we got lots of
+           dnl "`_POSIX_C_SOURCE' is not defined" in system headers with
+           dnl gcc 2.95.4 on FreeBSD 4.9!
+           WARN="$WARN -Wundef -Wno-long-long -Wsign-compare"
+         fi
+
+         if test "$gccnum" -ge "296"; then
+           dnl gcc 2.96 or later
+           WARN="$WARN -Wfloat-equal"
+         fi
+
+         if test "$gccnum" -gt "296"; then
+           dnl this option does not exist in 2.96
+           WARN="$WARN -Wno-format-nonliteral"
+         fi
+
+         dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
+         dnl on i686-Linux as it gives us heaps with false positives.
+         dnl Also, on gcc 4.0.X it is totally unbearable and complains all
+         dnl over making it unusable for generic purposes. Let's not use it.
+
+         if test "$gccnum" -ge "303"; then
+           dnl gcc 3.3 and later
+           WARN="$WARN -Wendif-labels -Wstrict-prototypes"
+         fi
+
+         if test "$gccnum" -ge "304"; then
+           # try these on gcc 3.4
+           WARN="$WARN -Wdeclaration-after-statement"
+         fi
+
+         for flag in $CPPFLAGS; do
+           case "$flag" in
+            -I*)
+              dnl Include path, provide a -isystem option for the same dir
+              dnl to prevent warnings in those dirs. The -isystem was not very
+              dnl reliable on earlier gcc versions.
+              add=`echo $flag | sed 's/^-I/-isystem /g'`
+              WARN="$WARN $add"
+              ;;
+           esac
+         done
+
+       fi dnl $ICC = no
+
+       CFLAGS="$CFLAGS $WARN"
+
+      AC_MSG_NOTICE([Added this set of compiler options: $WARN])
+
+    else dnl $GCC = yes
+
+      AC_MSG_NOTICE([Added no extra compiler options])
+
+    fi dnl $GCC = yes
+
+    dnl strip off optimizer flags
+    NEWFLAGS=""
+    for flag in $CFLAGS; do
+      case "$flag" in
+      -O*)
+        dnl echo "cut off $flag"
+        ;;
+      *)
+        NEWFLAGS="$NEWFLAGS $flag"
+        ;;
+      esac
+    done
+    CFLAGS=$NEWFLAGS
+
+]) dnl end of AC_DEFUN()
diff --git a/configure.in b/configure.in
index 99c8e3b..78d1aaf 100644
--- a/configure.in
+++ b/configure.in
@@ -219,6 +219,31 @@ AC_ARG_ENABLE(debug-all,
 	])
 
 
+dnl ************************************************************
+dnl option to switch on compiler debug options
+dnl
+AC_MSG_CHECKING([whether to enable pedantic and debug compiler options])
+AC_ARG_ENABLE(debug-build,
+AC_HELP_STRING([--enable-debug-build],[Enable pedantic debug options])
+AC_HELP_STRING([--disable-debug-build],[Disable debug options]),
+[ case "$enableval" in
+  no)
+       AC_MSG_RESULT(no)
+       ;;
+  *)   AC_MSG_RESULT(yes)
+
+    CPPFLAGS="$CPPFLAGS -DLIBSSH2DEBUG"
+    CFLAGS="$CFLAGS -g"
+
+    dnl set compiler "debug" options to become more picky, and remove
+    dnl optimize options from CFLAGS
+    CURL_CC_DEBUG_OPTS
+       ;;
+  esac
+ ],
+       AC_MSG_RESULT(no)
+)
+
 # Checks for header files.
 # AC_HEADER_STDC
 AC_CHECK_HEADERS([errno.h fcntl.h stdio.h stdlib.h unistd.h sys/uio.h sys/select.h])