{android,win32}/build.py: concatenate variables from the command line

android/build.py

@@ -154,5 +154,9 @@ configure = [
 
 ] + configure_args
 
+from build.cmdline import concatenate_cmdline_variables
+configure = concatenate_cmdline_variables(configure,
+    set(('CFLAGS', 'CXXFLAGS', 'CPPFLAGS', 'LDFLAGS', 'LIBS')))
+
 subprocess.check_call(configure, env=toolchain.env)
 subprocess.check_call(['/usr/bin/make', '--quiet', '-j12'], env=toolchain.env)

python/build/cmdline.py

@@ -0,0 +1,29 @@
+def concatenate_cmdline_variables(src, names):
+    """Find duplicate variable declarations on the given source list, and
+    concatenate the values of those in the 'names' list."""
+
+    # the result list being constructed
+    dest = []
+
+    # a map of variable name to destination list index
+    positions = {}
+
+    for item in src:
+        i = item.find('=')
+        if i > 0:
+            # it's a variable
+            name = item[:i]
+            if name in names:
+                # it's a known variable
+                if name in positions:
+                    # already specified: concatenate instead of
+                    # appending it
+                    dest[positions[name]] += ' ' + item[i + 1:]
+                    continue
+                else:
+                    # not yet seen: append it and remember the list
+                    # index
+                    positions[name] = len(dest)
+        dest.append(item)
+
+    return dest

win32/build.py

@@ -112,5 +112,9 @@ configure = [
 
 ] + configure_args
 
+from build.cmdline import concatenate_cmdline_variables
+configure = concatenate_cmdline_variables(configure,
+    set(('CFLAGS', 'CXXFLAGS', 'CPPFLAGS', 'LDFLAGS', 'LIBS')))
+
 subprocess.check_call(configure, env=toolchain.env)
 subprocess.check_call(['/usr/bin/make', '--quiet', '-j12'], env=toolchain.env)