diff --git a/configure.ac b/configure.ac
index 5e46b4b3a..1438bfd7f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -325,7 +325,10 @@ if test x$use_glibc_compat != xno; then
   #__fdelt_chk's params and return type have changed from long unsigned int to long int.
   # See which one is present here.
   AC_MSG_CHECKING(__fdelt_chk type)
-  AC_TRY_COMPILE([#define __USE_FORTIFY_LEVEL 2
+  AC_TRY_COMPILE([#ifdef _FORTIFY_SOURCE
+                    #undef _FORTIFY_SOURCE
+                  #endif
+                  #define _FORTIFY_SOURCE 2
                   #include <sys/select.h>
      extern "C" long unsigned int __fdelt_warn(long unsigned int);],[],
     [ fdelt_type="long unsigned int"],
diff --git a/src/m4/ax_boost_base.m4 b/src/m4/ax_boost_base.m4
index e025a7e1c..3f24d5ddc 100644
--- a/src/m4/ax_boost_base.m4
+++ b/src/m4/ax_boost_base.m4
@@ -112,6 +112,12 @@ if test "x$want_boost" = "xyes"; then
         ;;
     esac
 
+    dnl some arches may advertise a cpu type that doesn't line up with their
+    dnl prefix's cpu type. For example, uname may report armv7l while libs are
+    dnl installed to /usr/lib/arm-linux-gnueabihf. Try getting the compiler's
+    dnl value for an extra chance of finding the correct path.
+    libsubdirs="lib/`$CXX -dumpmachine 2>/dev/null` $libsubdirs"
+
     dnl first we check the system location for boost libraries
     dnl this location ist chosen if boost libraries are installed with the --layout=system option
     dnl or if you install boost with RPM