diff --git a/Makefile b/Makefile
index fbd63c4e..8918c429 100644
--- a/Makefile
+++ b/Makefile
@@ -24,6 +24,17 @@ TEMPFILE := $(shell mktemp -t chibi.XXXXXX)
 
 ########################################################################
 
+# Choose compiled library on MSYS
+ifeq ($(OS), Windows_NT)
+ifeq ($(PLATFORM),msys)
+EXCLUDE_WIN32_LIBS=1
+else
+EXCLUDE_POSIX_LIBS=1
+endif
+endif
+
+########################################################################
+
 CHIBI_COMPILED_LIBS = lib/chibi/filesystem$(SO) lib/chibi/weak$(SO) \
 	lib/chibi/heap-stats$(SO) lib/chibi/disasm$(SO) lib/chibi/ast$(SO) \
 	lib/chibi/emscripten$(SO)
diff --git a/appveyor.yml b/appveyor.yml
index 854f0f83..3adf6076 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -32,7 +32,7 @@ before_build:
     - if %BUILDTYPE%.==x86MinGW. set CC=c:/msys64/mingw32/bin/gcc
     - if %BUILDTYPE%.==x64MSYS. set CC=gcc
     - if %TOOLCHAIN%.==MSVC. set CC=cl.exe
-    - if %TOOLCHAIN%%BUILDSYSTEM%.==MinGWMSYS2. set EXARG=EXCLUDE_POSIX_LIBS=1
+    - if %TOOLCHAIN%%BUILDSYSTEM%.==MinGWMSYS2. set EXARG=
     - if %TOOLCHAIN%%BUILDSYSTEM%.==MSYSMSYS2. set EXARG=PLATFORM=msys
     - if %BUILDSYSTEM%.==CMAKE. cmake -G Ninja .