diff --git a/mex/build/matlab/configure.ac b/mex/build/matlab/configure.ac
index 0781883961096668da6c68d0ce8f35712e52e185..258b5d40fde45443df796781b6369fac6cf9fc29 100644
--- a/mex/build/matlab/configure.ac
+++ b/mex/build/matlab/configure.ac
@@ -58,6 +58,7 @@ CXXFLAGS="$CXXFLAGS -Wall -Wno-parentheses"
 
 AC_PROG_F77([gfortran g77 f77])
 AC_PROG_CC
+AC_PROG_CC_C99 # mjdgges DLL now uses C99 features (variable declared in for loop)
 AC_PROG_CXX
 AC_PROG_RANLIB
 AX_PROG_LN_S
diff --git a/mex/build/octave/configure.ac b/mex/build/octave/configure.ac
index 1e8a26d8c4e8bd617b4dc674fe174a1954e0c92c..4f3d5d4d43cabc4d731d32daa1775c4a49e7afbe 100755
--- a/mex/build/octave/configure.ac
+++ b/mex/build/octave/configure.ac
@@ -46,6 +46,7 @@ CXXFLAGS="$CXXFLAGS -Wall -Wno-parentheses"
 
 AC_PROG_F77([gfortran g77 f77])
 AC_PROG_CC
+AC_PROG_CC_C99 # mjdgges DLL now uses C99 features (variable declared in for loop)
 AC_PROG_CXX
 AC_PROG_RANLIB
 AX_PROG_LN_S