[PATCH] man: Document --list-all behaviour

[Arkadiusz Drabczyk]

---
I spent some time today trying to figure out why some libraries are
not listed when --list-all is used and I found that gkrellm.pc on my
system is broken as shown here:
https://git.srcbox.net/gkrellm/commit/?id=b9e3e896ef018307e2ba5475fb51605d5de0301a.
I believe that the manpage should mention that listing is stopped when
the first broken module is encountered.

 pkg-config.1 | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkg-config.1 b/pkg-config.1
index a147fc8..d7d3502 100644
--- a/pkg-config.1
+++ b/pkg-config.1
@@ -278,7 +278,10 @@ the .pc files, else a too large number of libraries will ordinarily be
 output.
 .TP
 .I "--list-all"
-List all modules found in the \fIpkg-config\fP path.
+List all modules found in the \fIpkg-config\fP path.  Listing is
+stopped when the first broken module without a name, version or
+description is encountered.  Use "--print-errors" to see error
+messages.
 .TP
 .I "--print-provides"
 List all modules the given packages provides.
-- 
2.9.0