contrib: srt: don't set redundant CFLAGS/CXXFLAGS

They are already using $(PIC) with $(HOSTVARS_PIC)

contrib/src/srt/rules.mak

@@ -11,8 +11,6 @@ ifeq ($(call need_pkg,"srt >= 1.3.2"),)
 PKGS_FOUND += srt
 endif
 
-SRT_CFLAGS   := $(CFLAGS) $(PIC)
-SRT_CXXFLAGS := $(CXXFLAGS) $(PIC)
 DEPS_srt = gnutls $(DEPS_gnutls)
 ifdef HAVE_WIN32
 DEPS_srt += pthreads $(DEPS_pthreads)
@@ -31,7 +29,7 @@ srt: srt-$(SRT_VERSION).tar.gz .sum-srt
 	mv srt-$(SRT_VERSION) $@ && touch $@
 
 .srt: srt toolchain.cmake
-	cd $< && $(HOSTVARS_PIC) CFLAGS="$(SRT_CFLAGS)" CXXFLAGS="$(SRT_CXXFLAGS)" $(CMAKE) \
+	cd $< && $(HOSTVARS_PIC) $(CMAKE) \
 		-DENABLE_SHARED=OFF -DUSE_GNUTLS=ON -DENABLE_CXX11=OFF -DCMAKE_INSTALL_LIBDIR=lib -DCMAKE_INSTALL_BINDIR=bin -DCMAKE_INSTALL_INCLUDEDIR=include
 	+$(CMAKEBUILD) $< --target install
 	touch $@