--- a/runConfigureICU
+++ b/runConfigureICU
@@ -239,8 +239,8 @@
         THE_COMP="the GNU C++"
         CC=gcc; export CC
         CXX=g++; export CXX
-        RELEASE_CFLAGS='-O3'
-        RELEASE_CXXFLAGS='-O3'
+        RELEASE_CFLAGS=' '
+        RELEASE_CXXFLAGS=' '
         DEBUG_CFLAGS='-g'
         DEBUG_CXXFLAGS='-g'
         ;;
