diff --git a/math/octave-forge-mboct-fem-pkg/Makefile b/math/octave-forge-mboct-fem-pkg/Makefile
index 309423be5436..21e6c1c5844d 100644
--- a/math/octave-forge-mboct-fem-pkg/Makefile
+++ b/math/octave-forge-mboct-fem-pkg/Makefile
@@ -1,6 +1,6 @@
 PORTNAME=	octave-forge-mboct-fem-pkg
 DISTVERSION=	0.2.2
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	math
 
 MAINTAINER=	stephen@FreeBSD.org
@@ -10,7 +10,7 @@ WWW=		https://packages.octave.org/
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/../COPYING
 
-USES=		octave autoreconf compiler:gcc-c++11-lib
+USES=		octave autoreconf perl5
 
 LIB_DEPENDS+=	libgtest.so:devel/googletest \
 		libmetis.so:math/metis \
@@ -24,9 +24,18 @@ RUN_DEPENDS+=	${OCTAVE_TARBALLS_DIR}/mboct-octave-pkg.tar.gz:math/octave-forge-m
 USE_GITHUB=	yes
 GH_ACCOUNT=	octave-user
 GH_PROJECT=	mboct-fem-pkg
+USE_PERL5=	build
 
 OCTAVE_SRC=	${GH_PROJECT}-${DISTVERSION}
 
 GNU_CONFIGURE=	yes
 
+pre-build:
+	# Hack that uses perl to pre-evaluate constexpr in C++ code that doesn't comply with C++ standard.
+	${CP} ${PATCHDIR}/print_epsilon.cpp ${WRKSRC}/.
+	${CXX} ${WRKSRC}/print_epsilon.cpp -o ${WRKSRC}/print_epsilon
+	${PERL} -i.bak -pe "s/std\:\:pow\(std\:\:numeric_limits\<double\>\:\:epsilon\(\)\,\ (0\.\d)\)/(`${WRKSRC}/print_epsilon`)**(\$$1)/e" ${WRKSRC}/__mboct_fem_pkg__.cc
+	${PERL} -i.bak -pe 's/sqrt\((\d+\.)\)/sqrt($$1)/e' ${WRKSRC}/__mboct_fem_pkg__.cc
+	${PERL} -i.bak -pe 's|sqrt\((\d+\.\/\d+\.)\)|sqrt(eval($$1))|e' ${WRKSRC}/__mboct_fem_pkg__.cc
+
 .include <bsd.port.mk>
diff --git a/math/octave-forge-mboct-fem-pkg/files/print_epsilon.cpp b/math/octave-forge-mboct-fem-pkg/files/print_epsilon.cpp
new file mode 100644
index 000000000000..077f993b17a8
--- /dev/null
+++ b/math/octave-forge-mboct-fem-pkg/files/print_epsilon.cpp
@@ -0,0 +1,7 @@
+#include<iostream>
+#include<limits>
+#include <iomanip>
+
+int main(){
+  std::cout << std::setprecision(20) << std::numeric_limits<double>::epsilon() << std::endl;
+}