diff --git a/mozilla/intl/lwbrk/src/Makefile.in b/mozilla/intl/lwbrk/src/Makefile.in
index 2673ebc4167..1f60e0b58d5 100644
--- a/mozilla/intl/lwbrk/src/Makefile.in
+++ b/mozilla/intl/lwbrk/src/Makefile.in
@@ -54,7 +54,7 @@ EXTRA_DSO_LDOPTS += $(MOZ_COMPONENT_LIBS)
 
 # Reserved name __STDC__ cannot be defined as a macro name on AIX or OpenVMS.
 # QNX simply objects to the way it's being redefined.
-ifeq (,$(filter AIX OpenVMS QNX,$(OS_ARCH)))
+ifeq (,$(filter AIX OpenVMS QNX HP-UX,$(OS_ARCH)))
 CFLAGS		+= -D__STDC__
 endif
 
diff --git a/mozilla/intl/uconv/src/Makefile.in b/mozilla/intl/uconv/src/Makefile.in
index 8a66d583fa8..dffc5c3ced8 100644
--- a/mozilla/intl/uconv/src/Makefile.in
+++ b/mozilla/intl/uconv/src/Makefile.in
@@ -113,7 +113,7 @@ CFLAGS		+= -DUSE_NSREG -D_IMPL_NS_INTL
 
 # Reserved name __STDC__ cannot be defined as a macro name on AIX or OpenVMS.
 # QNX simply objects to the way it's being redefined.
-ifeq (,$(filter AIX OpenVMS QNX,$(OS_ARCH)))
+ifeq (,$(filter AIX OpenVMS QNX HP-UX,$(OS_ARCH)))
 CFLAGS		+= -D__STDC__
 endif