[PATCH v4 10/19] grep & rev-list doc: stop promising libpcre for --perl-regexp

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Stop promising in our grep & rev-list options documentation that we're
always going to be using libpcre when given the --perl-regexp option.

Instead talk about using "Perl-compatible regular expressions" and
using these types of patterns using "a compile-time dependency".

Saying "libpcre" strongly suggests that we might be talking about
libpcre.so, which is always going to be v1. This change is part of a
series to add support for libpcre2 which comes with v2 of PCRE.

In the future we might use some completely unrelated library to
provide perl-compatible regular expression support. By wording the
documentation differently and not promising any specific version of
PCRE or ever PCRE at all we have more wiggle room to change the
implementation.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 Documentation/git-grep.txt         | 7 +++++--
 Documentation/rev-list-options.txt | 8 ++++++--
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 71f32f3508..5033483db4 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -161,8 +161,11 @@ OPTIONS
 
 -P::
 --perl-regexp::
-	Use Perl-compatible regexp for patterns. Requires libpcre to be
-	compiled in.
+	Use Perl-compatible regular expressions for patterns.
++
+Support for these types of regular expressions is an optional
+compile-time dependency. If Git wasn't compiled with support for them
+providing this option will cause it to die.
 
 -F::
 --fixed-strings::
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 5b7fa49a7f..9c44eae55d 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -93,8 +93,12 @@ endif::git-rev-list[]
 
 -P::
 --perl-regexp::
-	Consider the limiting patterns to be Perl-compatible regular expressions.
-	Requires libpcre to be compiled in.
+	Consider the limiting patterns to be Perl-compatible regular
+	expressions.
++
+Support for these types of regular expressions is an optional
+compile-time dependency. If Git wasn't compiled with support for them
+providing this option will cause it to die.
 
 --remove-empty::
 	Stop when a given path disappears from the tree.
-- 
2.11.0