graphics/pngquant: enable openmp, unbundle libimagequant

- Use graphics/libimagequant instead of bundled version [1]
- Re-add OPENMP option, enable it by default [2]

PR:	268931 [1]
PR:	268932 [2]

graphics/pngquant/Makefile

@@ -1,6 +1,7 @@
 PORTNAME=	pngquant
 PORTVERSION=	2.17.0
 DISTVERSIONSUFFIX=	-src
+PORTREVISION=	1
 CATEGORIES=	graphics
 MASTER_SITES=	https://pngquant.org/
 
@@ -11,22 +12,25 @@ WWW=		https://pngquant.org/
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/COPYRIGHT
 
-LIB_DEPENDS=	libpng.so:graphics/png
+LIB_DEPENDS=	libimagequant.so:graphics/libimagequant \
+		libpng.so:graphics/png
 
 WRKSRC=		${WRKDIR}/${PORTNAME}-${PORTVERSION}
 
 USES=		cpe gmake pkgconfig
 HAS_CONFIGURE=	yes
+CONFIGURE_ARGS=	--with-libimagequant
 
 PORTDOCS=	CHANGELOG README.md
 PLIST_FILES=	bin/pngquant \
 				man/man1/pngquant.1.gz
 
-OPTIONS_DEFINE=	OPTIMIZED_FLAGS LCMS2 DEBUG DOCS
+OPTIONS_DEFINE=	OPTIMIZED_FLAGS OPENMP LCMS2 DEBUG DOCS
 OPTIONS_DEFINE_i386=	SSE
 OPTIONS_DEFINE_amd64=	SSE
 LCMS2_DESC=	Support for ICC profiles via LCMS library
 OPTIMIZED_FLAGS_DESC=	${OPTIMIZED_CFLAGS_DESC}
+OPTIONS_DEFAULT=	OPENMP
 OPTIONS_DEFAULT_amd64=	SSE
 
 DEBUG_CONFIGURE_ON=	--enable-debug
@@ -34,6 +38,11 @@ DEBUG_CONFIGURE_ON=	--enable-debug
 LCMS2_CONFIGURE_WITH=	lcms2
 LCMS2_LIB_DEPENDS=	liblcms2.so:graphics/lcms2
 
+OPENMP_CONFIGURE_WITH=	openmp
+.if !exists(/usr/include/omp.h)
+OPENMP_USES=		compiler:gcc-c++11-lib
+.endif
+
 OPTIMIZED_FLAGS_CFLAGS=	-O3 -fstrict-aliasing \
 		-ffast-math -funroll-loops -fomit-frame-pointer \
 		-fexpensive-optimizations -ffinite-math-only \