Remove gcc5 packages.

* update_package_requires uses the latest version available, so haiku package
would then require a version 5.x of libgcc.
* Be sure to check that gcc_syslibs is installed and not gcc5_syslibs.

build/jam/repositories/HaikuPorts/x86

@@ -100,9 +100,6 @@ RemotePackageRepository HaikuPorts
 	gcc-4.8.5_2015_07_11-2
 	gcc_syslibs-4.8.5_2015_07_11-2
 	gcc_syslibs_devel-4.8.5_2015_07_11-2
-	gcc5-5.3.0_2015_07_27-1
-	gcc5_syslibs-5.3.0_2015_07_27-1
-	gcc5_syslibs_devel-5.3.0_2015_07_27-1
 	gettext-0.19.4-1
 	gettext_libintl-0.19.4-1
 	giflib-5.1.1-1
@@ -449,7 +446,6 @@ RemotePackageRepository HaikuPorts
 	freetype
 	gawk
 	gcc
-	gcc5
 	gcc_x86_gcc2
 	gettext
 	giflib

build/jam/repositories/HaikuPorts/x86_64

@@ -111,9 +111,6 @@ RemotePackageRepository HaikuPorts
 	gcc-4.8.5_2015_07_11-1
 	gcc_syslibs-4.8.5_2015_07_11-1
 	gcc_syslibs_devel-4.8.5_2015_07_11-1
-	gcc5-5.3.0_2015_07_27-1
-	gcc5_syslibs-5.3.0_2015_07_27-1
-	gcc5_syslibs_devel-5.3.0_2015_07_27-1
 	gettext-0.19.6-2
 	gettext_libintl-0.19.6-2
 	giflib-5.1.0-1
@@ -442,7 +439,6 @@ RemotePackageRepository HaikuPorts
 	fribidi
 	gawk
 	gcc
-	gcc5
 	gettext
 	giflib
 	git

build/jam/repositories/HaikuPorts/x86_gcc2

@@ -628,9 +628,6 @@ RemotePackageRepository HaikuPorts
 	gcc_x86-4.8.5_2015_07_11-2
 	gcc_x86_syslibs-4.8.5_2015_07_11-2
 	gcc_x86_syslibs_devel-4.8.5_2015_07_11-2
-	gcc5_x86-5.3.0_2015_07_27-1
-	gcc5_x86_syslibs-5.3.0_2015_07_27-1
-	gcc5_x86_syslibs_devel-5.3.0_2015_07_27-1
 	gcc6809_x86-4.6.1-2
 	gdk_pixbuf_x86-2.31.5-1
 	gdk_pixbuf_x86_devel-2.31.5-1
@@ -1062,7 +1059,6 @@ RemotePackageRepository HaikuPorts
 	gcal
 	gcc
 	gcc_x86
-	gcc5_x86
 	gcc6809_x86
 	getconf
 	getopt