Fix for wheel: pyppmd

Author: mreid-tt

spk/beets/Makefile

@@ -46,6 +46,11 @@ ifeq ($(call version_lt, $(TC_GCC), 5.0),1)
 WHEELS_CFLAGS += [pycryptodomex] -std=c11
 endif
 
+# [pyppmd]
+ifeq ($(call version_lt, $(TC_GCC), 5.0),1)
+WHEELS_CFLAGS += [pyppmd] -std=gnu11
+endif
+
 # TODO: The following plugins are currently unsupported due to dependency issues:
 # autobpm, bpd, metasync, and replaygain.