BaseTools: Update Edk2ToolsBuild.py to use multiple threads on Linux

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2640

Azure Pipelines agents have 2 threads. This commit has been shown to
reduce the build time in half on those agents.

Cc: Bob C Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Bob C Feng <bob.c.feng@intel.com>

BaseTools/Edk2ToolsBuild.py

@@ -11,6 +11,7 @@ import os
 import sys
 import logging
 import argparse
+import multiprocessing
 from edk2toolext import edk2_logging
 from edk2toolext.environment import self_describing_environment
 from edk2toolext.base_abstract_invocable import BaseAbstractInvocable
@@ -141,7 +142,8 @@ class Edk2ToolsBuild(BaseAbstractInvocable):
             return ret
 
         elif self.tool_chain_tag.lower().startswith("gcc"):
-            ret = RunCmd("make", "-C .", workingdir=shell_env.get_shell_var("EDK_TOOLS_PATH"))
+            cpu_count = self.GetCpuThreads()
+            ret = RunCmd("make", f"-C .  -j {cpu_count}", workingdir=shell_env.get_shell_var("EDK_TOOLS_PATH"))
             if ret != 0:
                 raise Exception("Failed to build.")
 
@@ -154,6 +156,18 @@ class Edk2ToolsBuild(BaseAbstractInvocable):
         logging.critical("Tool Chain not supported")
         return -1
 
+    def GetCpuThreads(self) -> int:
+        ''' Function to return number of cpus. If error return 1'''
+        cpus = 1
+        try:
+            cpus = multiprocessing.cpu_count()
+        except:
+            # from the internet there are cases where cpu_count is not implemented.
+            # will handle error by just doing single proc build
+            pass
+        return cpus
+
+
 
 def main():
     Edk2ToolsBuild().Invoke()