qt5: Rename BUILDROOT_COMPILER_C{,XX}FLAGS to BR_COMPILER_C{,XX}FLAGS

No functional change, but internal variables should be name BR_foo, not
BUILDROOT_foo (I think ..).

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/qt5/qt5base/qt5base-0002-mkspecs-files.patch

@@ -18,8 +18,8 @@ Index: b/mkspecs/devices/linux-buildroot-g++/qmake.conf
 +include(../common/linux_device_pre.conf)
 +
 +#modifications to gcc-base.conf
-+QMAKE_CFLAGS           += $${BUILDROOT_COMPILER_CFLAGS}
-+QMAKE_CXXFLAGS         += $${BUILDROOT_COMPILER_CXXFLAGS}
++QMAKE_CFLAGS           += $${BR_COMPILER_CFLAGS}
++QMAKE_CXXFLAGS         += $${BR_COMPILER_CXXFLAGS}
 +QMAKE_CXXFLAGS_RELEASE += -O3
 +
 +QMAKE_LIBS             += -lrt -lpthread -ldl

package/qt5/qt5base/qt5base.mk

@@ -169,8 +169,8 @@ define QT5BASE_CONFIGURE_CMDS
 		-nomake tests \
 		-device buildroot \
 		-device-option CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
-		-device-option BUILDROOT_COMPILER_CFLAGS="$(TARGET_CFLAGS)" \
-		-device-option BUILDROOT_COMPILER_CXXFLAGS="$(TARGET_CXXFLAGS)" \
+		-device-option BR_COMPILER_CFLAGS="$(TARGET_CFLAGS)" \
+		-device-option BR_COMPILER_CXXFLAGS="$(TARGET_CXXFLAGS)" \
 		-device-option EGLFS_PLATFORM_HOOKS_SOURCES="$(QT5BASE_EGLFS_PLATFORM_HOOKS_SOURCES)" \
 		-no-c++11 \
 		$(QT5BASE_CONFIGURE_OPTS) \