Add jobs option to make

Added '-j1' option since several users reported build errors with parallel make jobs

.SRCINFO

@@ -1,5 +1,5 @@
 # Generated by mksrcinfo v8
-# Sun Jan 31 23:28:00 UTC 2016
+# Sun Jan 31 23:50:00 UTC 2016
 pkgbase = florence
 	pkgdesc = A configurable on-screen virtual keyboard
 	pkgver = 0.6.3

PKGBUILD

@@ -26,11 +26,11 @@ build() {
 		--with-xtst \
 		--with-docs \
 		--disable-static
-	make
+	make -j1
 }
 
 package() {
 	cd "${srcdir}/${pkgname}-${pkgver}"
 
-	make DESTDIR="${pkgdir}" install
+	make -j1 DESTDIR="${pkgdir}" install
 }