contrib: aom: remove redundant flag

LDFLAGS is already set in HOSTVARS

contrib/src/aom/rules.mak

@@ -28,8 +28,6 @@ ifdef HAVE_WIN32
 DEPS_aom += pthreads $(DEPS_pthreads)
 endif
 
-AOM_LDFLAGS := $(LDFLAGS)
-
 AOM_CONF := \
 	-DCONFIG_RUNTIME_CPU_DETECT=1 \
 	-DCONFIG_MULTITHREAD=1 \
@@ -80,7 +78,7 @@ endif
 .aom: aom toolchain.cmake
 	rm -rf $(PREFIX)/include/aom
 	cd $< && rm -rf aom_build && mkdir -p aom_build
-	cd $</aom_build && LDFLAGS="$(AOM_LDFLAGS)" $(HOSTVARS) $(CMAKE) ../ $(AOM_CONF)
+	cd $</aom_build && $(HOSTVARS) $(CMAKE) ../ $(AOM_CONF)
 	+$(CMAKEBUILD) $</aom_build
 	$(call pkg_static,"aom_build/aom.pc")
 	+$(CMAKEBUILD) $</aom_build --target install