diff --git a/js-1.5-threadsafe.patch b/js-1.5-threadsafe.patch
new file mode 100644
index 0000000..b04a951
--- /dev/null
+++ b/js-1.5-threadsafe.patch
@@ -0,0 +1,17 @@
+diff -Naupr js.orig/src/Makefile.ref js/src/Makefile.ref
+--- js.orig/src/Makefile.ref	2003-11-15 01:10:55.000000000 +0100
++++ js/src/Makefile.ref	2006-07-24 17:06:59.000000000 +0200
+@@ -61,11 +61,11 @@ endif
+ 
+ ifdef JS_THREADSAFE
+ DEFINES += -DJS_THREADSAFE
+-INCLUDES += -I../../dist/$(OBJDIR)/include
++INCLUDES += $(shell nspr-config --cflags)
+ ifdef USE_MSVC
+ OTHER_LIBS += ../../dist/$(OBJDIR)/lib/libnspr${NSPR_LIBSUFFIX}.lib
+ else
+-OTHER_LIBS += -L../../dist/$(OBJDIR)/lib -lnspr${NSPR_LIBSUFFIX}
++OTHER_LIBS += $(shell nspr-config --libs)
+ endif
+ endif
+ 
diff --git a/js.spec b/js.spec
index ed810ce..d5e8324 100644
--- a/js.spec
+++ b/js.spec
@@ -3,7 +3,7 @@
 Summary: JavaScript interpreter and libraries
 Name: js
 Version: 1.5
-Release: 4%{?dist}
+Release: 5%{?dist}
 %if 0%{?_without_readline:1}
 License: MPL/GPL/LGPL
 %else
@@ -16,9 +16,10 @@ Patch0: js-make.patch
 Patch1: js-shlib.patch
 Patch2: js-1.5-va_copy.patch
 Patch3: js-ldflags.patch
+Patch4: js-1.5-threadsafe.patch
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root
 Requires:  perl(:MODULE_COMPAT_%(eval "`%{__perl} -V:version`"; echo $version))
-BuildRequires: perl >= 1:5.6.1, readline-devel
+BuildRequires: perl >= 1:5.6.1, readline-devel, nspr-devel
 Provides: libjs = %{version}-%{release}
 
 %description
@@ -41,10 +42,11 @@ you will need to install %{name}-devel.
 
 %prep
 %setup -q -n %{name}
-%patch0 -b .make
-%patch1 -b .shlib
+%patch0 -p0 -b .make
+%patch1 -p0 -b .shlib
 %patch2 -p1 -b .vacopy
-%patch3 -b .ldflags
+%patch3 -p0 -b .ldflags
+%patch4 -p1 -b .threadsafe
 %{__cp} src/perlconnect/README.html src/README.perlconnect.html
 
 # Create pkgconfig file
@@ -66,12 +68,14 @@ EOF
 %build
 export BUILD_OPT=1
 %{__make} -C src -f Makefile.ref \
+    JS_THREADSAFE="1" \
     XCFLAGS="%{optflags} -fPIC" \
     BUILD_OPT="1" \
 %if 0%{!?_without_readline:1}
     JS_READLINE="1" \
 %endif
     JS_PERLCONNECT="1"
+
 cd src/perlconnect
     MAKEFLAGS=-s %{__perl} Makefile.PL INSTALLDIRS=vendor
     %{__make} %{?_smp_mflags} OPTIMIZE="%{optflags}"
@@ -130,6 +134,10 @@ LD_LIBRARY_PATH=`pwd`/src/Linux_All_OPT.OBJ %{__make} -C src/perlconnect test
 
 
 %changelog
+* Mon Jul 24 2006 Matthias Saou <http://freshrpms.net/> 1.5-5
+- FC6 rebuild.
+- Enable JS_THREADSAFE in the build (#199696), add patch and nspr build req.
+
 * Mon Mar  6 2006 Matthias Saou <http://freshrpms.net/> 1.5-4
 - FC5 rebuild.