diff --git a/octave-iso2mesh.spec b/octave-iso2mesh.spec
index b402cc9..76fd6a1 100644
--- a/octave-iso2mesh.spec
+++ b/octave-iso2mesh.spec
@@ -2,7 +2,7 @@
 
 Name:           octave-%{octpkg}
 Version:        1.9.1
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        A 3D surface and volumetric mesh generator for MATLAB/Octave
 # Main package: GPLv3+
 # Meshfix: GPLv2+
@@ -259,12 +259,21 @@ savemsgpack savenifti saveubjson zlibdecode zlibencode
 mv *.m inst/
 mv img2mesh.fig inst/
 
+# Fix jmeshlib build flags
+sed -e "s|-Wall|%{optflags}|;s|^LIBS = |&$RPM_LD_FLAGS |" \
+    -i tools/meshfix/contrib/JMeshLib/test/Makefile
+
+# Fix tetgen build flags
+sed -e "s|^\(CXXFLAGS = \).*|\1%{optflags} $RPM_LD_FLAGS|" \
+    -e "s|-O0|%{optflags} $RPM_LD_FLAGS|" \
+    -i tools/tetgen/makefile
+
 %build
 %set_build_flags
 pushd tools
 # can't use make_build macro below because parallel make with CGAL exhausts
 # vm's memory and crash the building process, use sequential make instead
-make
+make USERCCFLAGS="%{optflags}"
 popd
 pushd bin
 ln -s tetgen1.5 tetgen
@@ -318,6 +327,10 @@ install -m 0755 -vp  bin/* %{buildroot}%{_libexecdir}/%{octpkg}/
 %doc sample
 
 %changelog
+* Mon Nov 25 2019 Jerry James <loganjerry@gmail.com> - 1.9.1-4
+- Rebuild for mpfr 4
+- Use Fedora build flags when building jmeshlib and tetgen
+
 * Fri Oct 11 2019 Qianqian Fang <fangqq@gmail.com> - 1.9.1-3
 - Define octave package-level dependency via the DESCRIPTION file
 - Remove gmp-devel from Requires