diff --git a/3rdparty/Makefile b/3rdparty/Makefile
index 78b0c43e..721ddd5a 100644
--- a/3rdparty/Makefile
+++ b/3rdparty/Makefile
@@ -147,6 +147,10 @@ STRIP = strip
 
 # There is no uname under windows, but we can guess we are there with the COMSPEC env.var
 # Windows specific
+ifdef ComSpec
+# sometimes, it is ComSpec, sometimes it is COMSPEC
+COMSPEC = $(ComSpec)
+endif
 ifdef COMSPEC
 WIN32 = 1
 RANLIB = ranlib
diff --git a/src/Makefile b/src/Makefile
index 67f3308d..dcc848f2 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -97,6 +97,10 @@ PKG_CONFIG ?= pkg-config
 
 # There is no uname under windows, but we can guess we are there with the COMSPEC env.var
 # Windows specific
+ifdef ComSpec
+# sometimes, it is ComSpec, sometimes it is COMSPEC
+COMSPEC = $(ComSpec)
+endif
 ifdef COMSPEC
   DELCOMMAND = rm -f
   MKDIR = mkdir -p