--- a/js/src/config/rules.mk
+++ b/js/src/config/rules.mk
@@ -1482,17 +1482,17 @@ normalizepath = $(foreach p,$(1),$(shell
 else
 # assume MSYS
 #  We use 'pwd -W' to get DOS form of the path.  However, since the given path
 #  could be a file or a non-existent path, we cannot call 'pwd -W' directly
 #  on the path.  Instead, we extract the root path (i.e. "c:/"), call 'pwd -W'
 #  on it, then merge with the rest of the path.
 root-path = $(shell echo $(1) | sed -e "s|\(/[^/]*\)/\?\(.*\)|\1|")
 non-root-path = $(shell echo $(1) | sed -e "s|\(/[^/]*\)/\?\(.*\)|\2|")
-normalizepath = $(foreach p,$(1),$(if $(filter /%,$(1)),$(shell cd $(call root-path,$(1)) && pwd -W)$(call non-root-path,$(1)),$(1)))
+normalizepath = $(foreach p,$(1),$(if $(filter /%,$(1)),$(patsubst %/,%,$(shell cd $(call root-path,$(1)) && pwd -W))/$(call non-root-path,$(1)),$(1)))
 endif
 else
 normalizepath = $(1)
 endif
 
 _srcdir = $(call normalizepath,$(srcdir))
 ifdef JAVA_SOURCEPATH
 SP = $(subst $(SPACE),$(SEP),$(call normalizepath,$(strip $(JAVA_SOURCEPATH))))