torsmo: use correct variable for HELP2MAN preset

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/torsmo/torsmo.mk

@@ -11,7 +11,7 @@ TORSMO_INSTALL_STAGING = NO
 TORSMO_INSTALL_TARGET = YES
 
 # help2man doesn't work when cross compiling
-TORSMO_CONF_ENV = HELP2MAN=''
+TORSMO_CONF_ENV = ac_cv_path_HELP2MAN=''
 TORSMO_CONF_OPT = --x-includes="-I$(STAGING_DIR)/usr/include/X11" --x-libraries="-I$(STAGING_DIR)/usr/lib" --with-x
 
 TORSMO_DEPENDENCIES = xserver_xorg-server