modconv: add missing source in Makefile

Author: emily-is-my-username

Makefile

@@ -163,7 +163,7 @@ ifeq ($(CROSS),arm64)
         CPPFLAGS += -Ithird_party/vixl/src -Ithird_party/vixl/src/aarch64
 endif
 SUPPORT_SRCS := src/support/file.cc src/support/mem4g.cc src/support/zfile.cc
-SUPPORT_SRCS += src/supportpsx/binloader.cc src/supportpsx/ps1-packer.cc
+SUPPORT_SRCS += src/supportpsx/adpcm.cc src/supportpsx/binloader.cc src/supportpsx/ps1-packer.cc
 SUPPORT_SRCS += third_party/fmt/src/os.cc third_party/fmt/src/format.cc
 SUPPORT_SRCS += third_party/ucl/src/n2e_99.c third_party/ucl/src/alloc.c
 SUPPORT_SRCS += $(wildcard third_party/iec-60908b/*.c)