Handle review comments.

Author: abidh

flang/docs/FlangDriver.md

@@ -618,10 +618,10 @@ nvfortran defines `-fast` as
 
 ## FCC_OVERRIDE_OPTIONS
 
-The environment variable `FCC_OVERRIDE_OPTIONS` can be used to apply a list of
-edits to the input argument lists. The value of this environment variable is
-a space separated list of edits to perform. These edits are applied in order to
-the input argument lists. Edits should be one of the following forms:
+The environment variable `FCC_OVERRIDE_OPTIONS` can be used to edit flang's
+command line arguments. The value of this variable is a space-separated list of
+edits to perform. The edits are applied in the order in which they appear in
+`FCC_OVERRIDE_OPTIONS`. Each edit should be one of the following forms:
 
 - `#`: Silence information about the changes to the command line arguments.
 

flang/test/Driver/fcc_override.f90

@@ -1,5 +1,5 @@
 ! RUN: env FCC_OVERRIDE_OPTIONS="#+-Os +-Oz +-O +-O3 +-Oignore +a +b +c xb Xa Omagic ^-###  " %flang -target x86_64-unknown-linux-gnu %s -O2 b -O3 2>&1 | FileCheck %s
-! RUN: env FCC_OVERRIDE_OPTIONS="x-Werror +-g" %flang -target x86_64-unknown-linux-gnu -Werror %s -c -### 2>&1 | FileCheck %s -check-prefix=RM-WERROR
+! RUN: env FCC_OVERRIDE_OPTIONS="x-Werror +-g" %flang --target=x86_64-unknown-linux-gnu -Werror %s -c -### 2>&1 | FileCheck %s -check-prefix=RM-WERROR
 ! RUN: env FCC_OVERRIDE_OPTIONS="x-Werror" %flang --config=%S/Inputs/config-7.cfg -### %s -c  2>&1 | FileCheck %s -check-prefix=CONF
 
 ! CHECK: "-fc1"