freeglut: add glu to requirements in .pc file

Fix https://github.com/mxe/mxe/issues/1434
See https://github.com/mxe/mxe/pull/1429
See http://stackoverflow.com/a/17451000

src/freeglut-1-fixes.patch

@@ -72,3 +72,25 @@ index 1111111..2222222 100644
  ENDIF()
  CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/freeglut.pc.in ${CMAKE_BINARY_DIR}/freeglut.pc @ONLY)
  INSTALL(FILES ${CMAKE_BINARY_DIR}/freeglut.pc DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig/ RENAME ${PC_FILENAME})
+
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Boris Nagaev <bnagaev@gmail.com>
+Date: Thu, 14 Jul 2016 19:15:17 +0300
+Subject: [PATCH] add glu to requirements in .pc file
+
+glu.pc is generated by mxe-conf and it adds -lglu32 to linker flags.
+libglu32.a defines gluUnProject and other symbols used by users of GLU.
+
+Fix https://github.com/mxe/mxe/issues/1434
+See https://github.com/mxe/mxe/pull/1429
+See http://stackoverflow.com/a/17451000
+
+diff --git a/freeglut.pc.in b/freeglut.pc.in
+index 1111111..2222222 100644
+--- a/freeglut.pc.in
++++ b/freeglut.pc.in
+@@ -8,3 +8,4 @@ Version: @VERSION_MAJOR@.@VERSION_MINOR@.@VERSION_PATCH@
+ Libs: -L${libdir} -l@PC_LIBNAME@
+ Libs.private: @PC_LIBS_PRIVATE@
+ Cflags: -I${includedir} @PC_CFLAGS@
++Requires: glu