gnuplot: Added package.

About the patch: Gnuplot build process includes the compilation of some
custom binaries which are subsequently used to generate help files/docs.
Since those binaries are compiled for TARGET, this breaks the build on
the HOST. The patch disables the generation of those binaries (and the
documentation).

Signed-off-by: Matteo Cicuttin <datafl4sh@toxicnet.eu>

utils/gnuplot/Makefile

@@ -0,0 +1,47 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=gnuplot
+PKG_VERSION:=5.2.8
+PKG_RELEASE:=1
+PKG_MAINTAINER:=Matteo Cicuttin <datafl4sh@toxicnet.eu>
+
+PKG_BUILD_DIR:=$(BUILD_DIR)/gnuplot-$(PKG_VERSION)
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=@SF/gnuplot
+PKG_HASH:=60a6764ccf404a1668c140f11cc1f699290ab70daa1151bb58fed6139a28ac37
+PKG_CAT:=zcat
+PKG_FIXUP:=autoreconf
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/gnuplot
+  SECTION:=utils
+  CATEGORY:=Utilities
+  DEPENDS:=+zlib +libgd
+  TITLE:=A portable command-line driven graphing utility
+  URL:=http://www.gnuplot.info/
+endef
+
+CONFIGURE_ARGS += \
+    --without-cairo \
+    --with-qt=no \
+    --without-lua \
+    --without-latex \
+    --without-libcerf
+
+# Since Qt is disabled there is no C++ code, so CXX is forced
+# to CC in order to avoid dependency on libstdcpp. This is 
+# horrible, but 'DEPENDS:=+libstdcpp' does not work for some
+# reason. 
+define Build/Compile
+	$(MAKE) -C $(PKG_BUILD_DIR) \
+		CXX="$(TARGET_CC_NOCACHE)"  
+endef
+
+define Package/gnuplot/install
+	$(INSTALL_DIR) $(1)/usr/bin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/src/gnuplot $(1)/usr/bin
+endef
+
+$(eval $(call BuildPackage,gnuplot))
+

utils/gnuplot/patches/010-remove_doc_from_makefile.patch

@@ -0,0 +1,13 @@
+Index: gnuplot-5.2.8/Makefile.am
+===================================================================
+--- gnuplot-5.2.8.orig/Makefile.am
++++ gnuplot-5.2.8/Makefile.am
+@@ -1,7 +1,7 @@
+ ## Process this file with automake to produce Makefile.in -*-Makefile-*-
+ AUTOMAKE_OPTIONS = foreign
+ 
+-SUBDIRS = config m4 term src docs man demo tutorial share
++SUBDIRS = config m4 term src man tutorial share
+ 
+ EXTRA_DIST = BUGS Copyright FAQ.pdf GNUmakefile INSTALL INSTALL.gnu \
+ Makefile.maint PATCHLEVEL PGPKEYS README RELEASE_NOTES \