Added gcc buildrequires.

gsl.spec

@@ -1,7 +1,7 @@
 Summary: The GNU Scientific Library for numerical analysis
 Name: gsl
 Version: 2.4
-Release: 4%{?dist}
+Release: 5%{?dist}
 URL: http://www.gnu.org/software/gsl/
 # info part of this package is under GFDL license
 # eigen/nonsymmv.c and eigen/schur.c
@@ -14,6 +14,8 @@ Patch0: gsl-1.10-lib64.patch
 # http://lists.gnu.org/archive/html/bug-gsl/2015-12/msg00012.html
 Patch1: gsl-tol.patch
 Patch2: gsl-test.patch
+
+BuildRequires: gcc
 BuildRequires: pkgconfig
 
 %description
@@ -99,6 +101,9 @@ fi
 %{_mandir}/man3/*.3*
 
 %changelog
+* Wed Feb 28 2018 Susi Lehtola <jussilehtola@fedoraproject.org> - 2.4-5
+- Added gcc buildrequires.
+
 * Wed Feb 07 2018 Fedora Release Engineering <releng@fedoraproject.org> - 2.4-4
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild