diff --git a/configure/os/CONFIG.hpux-parisc.hpux-parisc b/configure/os/CONFIG.hpux-parisc.hpux-parisc
index 8a14e65a1..6ff666b3c 100644
--- a/configure/os/CONFIG.hpux-parisc.hpux-parisc
+++ b/configure/os/CONFIG.hpux-parisc.hpux-parisc
@@ -15,9 +15,9 @@ AR = ar -rc
 LD = ld -r
 
 # Configure OS vendor C compiler
-CONFORM_CFLAGS_ANSI = -Aa
-CONFORM_CFLAGS_STRICT = -Aa
-CONFORM_CFLAGS_TRAD = -Ac
+CONFORM_CFLAGS_ANSI = -Aa -mt
+CONFORM_CFLAGS_STRICT = -Aa -mt
+CONFORM_CFLAGS_TRAD = -Ac -mt
 
 # Portability across different PA-RISC architecture versions
 CODE_CFLAGS = +DAportable +z