diff --git a/gambit-c.spec b/gambit-c.spec
index cb7403a..464eaf5 100644
--- a/gambit-c.spec
+++ b/gambit-c.spec
@@ -9,6 +9,7 @@
 %if 0%{?el6}
 %ifarch ppc64
 %if ! %{with ppc64opt2}
+%global disable_c_opt 1
 %global optflags %(echo %{optflags} | sed 's/-O2 /-O1 /')
 %endif
 %endif # ppc64
@@ -79,9 +80,29 @@ chmod -x lib/*.{c,h}
 %build
 # disable expensive optimizations on specified platforms
 # see INSTALL.txt
+%ifarch s390 %{arm}
+%global disable_gcc_opts 1
+%endif
+
+%if 0%{?fedora}
+%if 0%{?fedora} <= 21
+%global disable_gcc_opts 1
+%endif
+%endif
+
+%if 0%{?rhel}
+%if 0%{?rhel} <= 7
+%global disable_gcc_opts 1
+%endif
+%endif
+
 %configure --enable-single-host \
+%if 0%{?disable_c_opt:1}
+%else
            --enable-c-opt \
-%ifnarch s390 %{arm}
+%endif
+%if 0%{?disable_gcc_opts:1}
+%else
            --enable-gcc-opts \
 %endif
            --bindir=%{_libdir}/%{name}/bin \