package/pugixml: fix configuration options

Commit upstream 1c5a0bb32583fd294022e68e66b541bf6ff71a67
":sparkles: Update CMake to modern approach" removed all feature
toogles, so starting from release v1.11 any flag passed in BUILD_DEFINES
was completely ignored during the build.
Version 1.11.4 was in use in buildroot since February 2021.

Commit upstream 0f1e75a902ef1751dd63a67fe223b5e8daf4c7f1
"Re-introduced the custom build defines" added PUGIXML_BUILD_DEFINES to
release v1.12, but BUILD_DEFINES is still completely ignored during the
build.
Version 1.12.1 is in use in buildroot since March 2022.

So switch the config options to use PUGIXML_BUILD_DEFINES instead of
BUILD_DEFINES.

Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Theo Debrouwere <t.debrouwere@televic.com>
Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit cc3a4a7b1de7b158354c650d234339e8a969a730)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/pugixml/pugixml.mk

@@ -29,11 +29,11 @@ ifeq ($(BR2_PACKAGE_PUGIXML_HEADER_ONLY),y)
 PUGIXML_BUILD_DEFINES += PUGIXML_HEADER_ONLY
 endif
 
-PUGIXML_CONF_OPTS += -DBUILD_DEFINES="$(subst $(space),;,$(PUGIXML_BUILD_DEFINES))"
+PUGIXML_CONF_OPTS += -DPUGIXML_BUILD_DEFINES="$(subst $(space),;,$(PUGIXML_BUILD_DEFINES))"
 
 HOST_PUGIXML_CONF_OPTS += \
 	-DBUILD_PKGCONFIG=ON \
-	-DBUILD_DEFINES="$(subst $(space),;,$(HOST_PUGIXML_BUILD_DEFINES))"
+	-DPUGIXML_BUILD_DEFINES="$(subst $(space),;,$(HOST_PUGIXML_BUILD_DEFINES))"
 
 $(eval $(cmake-package))
 $(eval $(host-cmake-package))