add BuildRequires: gcc

Reference: https://fedoraproject.org/wiki/Changes/Remove_GCC_from_BuildRoot

libgdiplus.spec

@@ -13,6 +13,7 @@ Source0:        http://download.mono-project.com/sources/%{name}/%{name}-%{versi
 
 # drop -Wno-format so the default -Werror=format-security works
 Patch1:         libgdiplus-2.10.9-format.patch
+BuildRequires:  gcc
 BuildRequires:  freetype-devel glib2-devel libjpeg-devel libtiff-devel
 BuildRequires:  libpng-devel fontconfig-devel
 BuildRequires:  cairo-devel giflib-devel libexif-devel