Added set computer arch via config

Signed-off-by: Dimitris Zlatanidis <d.zlatanidis@gmail.com>

ChangeLog.txt

@@ -1,6 +1,7 @@
 3.3.1 - 07/10/2017
 Added:
 - Set Slackware version via configuration file /etc/slpkg/slpkg.conf
+- Set computer architecture via configuration file /etc/slpkg/slpkg.conf
 
 3.3.0 - 01/10/2017
 Fixed: 

conf/slpkg.conf

@@ -26,10 +26,12 @@
 # Slackware release "stable" or "current".
 RELEASE=stable
 
-# Set Slackware version. It's not necessary only for some reasons.
-# Default is "off".
+# Set Slackware version if it's necessary. Default is "off".
 SLACKWARE_VERSION=off
 
+# Set computer architecture if it's necessary. Default is "off".
+COMP_ARCH=off
+
 # Build directory for repository "sbo" slackbuilds.org. In this 
 # directory downloaded sources and scripts for building.
 BUILD_PATH=/tmp/slpkg/build/

slpkg/__metadata__.py

@@ -98,6 +98,7 @@ class MetaData(object):
     _conf_slpkg = {
         "RELEASE": "stable",
         "SLACKWARE_VERSION": "off",
+        "COMP_ARCH": "off",
         "REPOSITORIES": ["slack", "sbo", "rlw", "alien",
                          "slacky", "conrad", "slonly",
                          "ktown{latest}", "multi", "slacke{18}",
@@ -150,6 +151,7 @@ class MetaData(object):
     # Set values from configuration file
     slack_rel = _conf_slpkg["RELEASE"]
     slackware_version = _conf_slpkg["SLACKWARE_VERSION"]
+    comp_arch = _conf_slpkg["COMP_ARCH"]
     build_path = _conf_slpkg["BUILD_PATH"]
     sbosrcarch = _conf_slpkg["SBOSRCARCH"]
     sbosrcarch_link = _conf_slpkg["SBOSRCARCH_LINK"]
@@ -238,7 +240,10 @@ class MetaData(object):
     slackpkg_lib_path = "/var/lib/slackpkg/"
 
     # computer architecture
-    arch = os.uname()[4]
+    if comp_arch == "off" or comp_arch == "OFF":
+        arch = os.uname()[4]
+    else:
+        arch = comp_arch
 
     # get sbo OUTPUT enviroment variable
     try:

slpkg/config.py

@@ -44,6 +44,7 @@ class Config(object):
         conf_args = [
             "RELEASE",
             "SLACKWARE_VERSION",
+            "COMP_ARCH",
             "BUILD_PATH",
             "PACKAGES",
             "PATCHES",