rtems/bsps: Fix building 3rd party packages with various options

- Fix locating valid tools and BSP. If either is found in the
  staging area use that else use the specific --with-* option
  and if not present use the --prefix.

- Locate the tools by checking if the arch's C compiler is a valid
  file. No other checks are made on the tools.

- Locate a BSB by checking for a valid pkgconfig file for the
  BSP.

- Only filter flags if the BSP is in the staging area

Closes #3893

rtems/config/rtems-bsp.cfg

@@ -10,10 +10,10 @@
 # Keeping the package's installed path in the RTEMS install path and separate
 # to the tools lets the tools version vary independently.
 #
-# Provide the path to the RTEMS tools is not in the prefix with the
+# Provide the path to the RTEMS tools if not in the prefix with the
 # --with-tools option. If --with-tools is not provided use the prefix.
 #
-# Provide the path to the installed RTEMS kernel is not in the prefix with the
+# Provide the path to the installed RTEMS kernel if not in the prefix with the
 # --with-rtems option. If --with-rtems is not provided use the prefix.
 #
 # Note, only a single path (--with-rtems) for the RTEMS kernel and any other
@@ -31,6 +31,14 @@
  %define rtems_bsp_error 1
 %endif
 
+#
+# Set up how we manage pkgconfig. Enable support when crosscompiling,
+# and filter specific optimisation and warning from the flags that
+# RTEMS exports.
+#
+%{pkgconfig crosscompile yes}
+%{pkgconfig filter-flags yes}
+
 #
 # We need a host from the user to specifiy the RTEMS architecture and major
 # version. It can be defined in rtems_host.
@@ -60,10 +68,13 @@
 # root.
 #
 %ifn %{defined with_tools}
- %if %{install_mode} == staging
+ %if %{install_mode} == staging && \
+      %{path check isfile %{stagingroot}/bin/%{_host}-%{_host_cc}}
+  %define rtems_tools_staged 1
   %define with_tools %{stagingroot}
   %define rtems_waf_tools --rtems-tools=%{with_tools}
  %else
+  %define rtems_tools_staged 1
   %define with_tools %{_prefix}
   %define rtems_waf_tools %{nil}
  %endif
@@ -71,11 +82,20 @@
  %define rtems_waf_tools --rtems-tools=%{with_tools}
 %endif
 
+%define rtems_host_cc_valid \
+         %{path check isfile %{with_tools}/bin/%{_host}-%{_host_cc}}
+%if !%{rtems_host_cc_valid} && %{rtems_bsp_error} && !%{_rsb_getting_source}
+ %error RTEMS tools not found (%{_host}-%{_host_cc}) found; Please check the --with-tools option or --prefix.
+%endif
+
 %ifn %{defined with_rtems}
- %if %{install_mode} == staging
+ %{pkgconfig prefix %{stagingroot}/lib/pkgconfig}
+ %if %{install_mode} == staging && %{pkgconfig check %{_host}-%{rtems_bsp}}
+  %define rtems_bsp_staged 1
   %define with_rtems %{stagingroot}
   %define rtems_waf_rtems --rtems=%{with_rtems}
  %else
+  %define rtems_bsp_staged 0
   %define with_rtems %{_prefix}
   %define rtems_waf_rtems %{nil}
  %endif
@@ -83,6 +103,18 @@
  %define rtems_waf_rtems --rtems=%{with_rtems}
 %endif
 
+#
+# Set the pkgconfig prefix path to the RTEMS prefix.
+#
+%{pkgconfig prefix %{with_rtems}/lib/pkgconfig}
+
+#
+# Check we can find the BSP's pkgconfig file.
+#
+%if !%{pkgconfig check %{_host}-%{rtems_bsp}} && %{rtems_bsp_error} && !%{_rsb_getting_source}
+ %error RTEMS BSP not found (%{_host}-%{rtems_bsp}.pc); Please check the --with-rtems option or --prefix.
+%endif
+
 #
 # Set the path to the tools.
 #
@@ -111,15 +143,6 @@
 %define _localedir        %{_datadir}/locale
 %define _localstatedir    %{_exec_prefix}/var
 
-#
-# Set up how we manage pkgconfig. Set the prefix path to the RTEMS prefix,
-# enable support when crosscompiling, and filter specific optimisation and
-# warning from the flags that RTEMS exports.
-#
-%{pkgconfig prefix %{with_rtems}/lib/pkgconfig}
-%{pkgconfig crosscompile yes}
-%{pkgconfig filter-flags yes}
-
 #
 # The RTEMS BSP Flags
 #
@@ -155,9 +178,9 @@
 
 #
 # Filter the flags converting any prefix to the staging path if this is a
-# staging build.
+# staging build of the BSP.
 #
-%if %{install_mode} == staging
+%if %{rtems_bsp_staged}
  %define staging_filter sed -e 's|%{_prefix}|%{stagingroot}|g'
  %define rtems_bsp_prefix     $(echo %{rtems_bsp_prefix}   | %{staging_filter})
  %define rtems_bsp_includes   $(echo %{rtems_bsp_includes} | %{staging_filter})