If not done, it would leak the memory as address sanitizer reports:
==1294==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 40 byte(s) in 1 object(s) allocated from:
#0 0x7fa7a94b7602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
#1 0x44c7a7 in __config_new girepository/cmph/cmph_structs.c:11
#2 0x44aaa7 in cmph_config_new girepository/cmph/cmph.c:291
#3 0x446fb5 in _gi_typelib_hash_builder_prepare girepository/gthash.c:114
#4 0x406cf7 in add_directory_index_section girepository/girmodule.c:270
#5 0x409ee6 in _g_ir_module_build_typelib girepository/girmodule.c:546
#6 0x404ada in main tools/compiler.c:217
#7 0x7fa7a70d482f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
==4091==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 40 byte(s) in 1 object(s) allocated from:
#0 0x7fc20c854602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)
#1 0x44a3f3 in cmph_io_vector_new girepository/cmph/cmph.c:228
#2 0x44a965 in cmph_io_vector_adapter girepository/cmph/cmph.c:276
#3 0x446f9f in _gi_typelib_hash_builder_prepare girepository/gthash.c:113
#4 0x406cf7 in add_directory_index_section girepository/girmodule.c:270
#5 0x409ee6 in _g_ir_module_build_typelib girepository/girmodule.c:546
#6 0x404ada in main tools/compiler.c:217
#7 0x7fc20a47182f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
79225a62c0