sb: Add support for building RTEMS 3rd party packages.

Remove the 'opt' from various macros and shell variables.

Add pkgconfig to the checks to make it clear the check is a
pkgconfig check.

Add NTP support as the first package to be built using the RSB.

Split the RTEMS URL's out from the base bset file into a separate
file that be included by other files.

Add an RTEMS BSP configuration file to help abstract the process
of building 3rd party packages.

Clean the cross and canadian cross support up so we can cleanly support
cross and canadian cross building.

Refactor the pkgconfig support and clean up the PC file handling of
loading modules.

Add support for %{?..} to return false if a macro is %{nil}.

Add %{pkgconfig ..} support to allow better control of access RTEMS
pkgconfig files.

bare/config/devel/gettext-0.18.3.1-1.cfg

@@ -13,6 +13,6 @@
 #
 # The GetText build instructions. We use 0.x.x Release 1.
 #
-%ifn %{check gettext}
+%ifn %{pkgconfig check gettext}
  %include %{_configdir}/gettext-0-1.cfg
 %endif

bare/config/devel/glib-2.39.3-1.cfg

@@ -15,6 +15,6 @@
 #
 # The GLib build instructions. We use 2.x.x Release 1.
 #
-%ifn %{check glib-2.0}
+%ifn %{pkgconfig check glib-2.0}
  %include %{_configdir}/glib-2-1.cfg
 %endif

bare/config/devel/libffi-3.0.13-1.cfg

@@ -24,6 +24,6 @@
 #
 # The LibFFI build instructions. We use 3.x.x Release 1.
 #
-%ifn %{check libffi >= 3}
+%ifn %{pkgconfig check libffi >= 3}
  %include %{_configdir}/libffi-3-1.cfg
 %endif

bare/config/devel/libiconv-1.14-1.cfg

@@ -14,7 +14,7 @@
 # The Libiconv build instructions. We use 0.x.x Release 1.
 #
 %if %{_host_os} == win32
- %ifn %{check iconv >= %{libiconv_version}}
+ %ifn %{pkgconfig check iconv >= %{libiconv_version}}
   %include %{_configdir}/libiconv-1-1.cfg
  %endif
 %endif

bare/config/devel/pixman-0.32.4-1.cfg

@@ -13,6 +13,6 @@
 #
 # The Pixman build instructions. We use 0.x.x Release 1.
 #
-%ifn %{check pixman-1}
+%ifn %{pkgconfig check pixman-1}
  %include %{_configdir}/pixman-0-1.cfg
 %endif

bare/config/devel/texane-stlink-1.cfg

@@ -45,7 +45,7 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
   CFLAGS_FOR_BUILD="-g -O2 -Wall" \
 %endif
   CPPFLAGS="-I $SB_TMPPREFIX/include/libusb-1.0" \
-  CFLAGS="$SB_OPT_FLAGS" \
+  CFLAGS="$SB_CFLAGS" \
   LDFLAGS="-L $SB_TMPPREFIX/lib" \
   ./configure \
     --build=%{_build} --host=%{_host} \