development/ex-vi: Don't override environment CC.

Signed-off-by: B. Watson <yalhcru@gmail.com>

development/ex-vi/ex-vi.SlackBuild

@@ -92,7 +92,7 @@ sed -i -e "/^#define/s,\\(TUBESIZE *\\).*$,\\1 $(( TUBECOLS * TUBELINES ))," \
 # To avoid conflicts with Slackware's elvis and/or vim, we install to /opt and
 # include a login script to set PATH and MANPATH.
 make -j1 all install \
-  CC="gcc $SLKCFLAGS" \
+  RPMCFLAGS="$SLKCFLAGS" \
   MANDIR=/opt/$PRGNAM/man \
   PREFIX=/opt/$PRGNAM \
   INSTALL=install \