manpage: add environment variables section (firmware, decoders path)

Add the SIGROK_FIRMWARE_DIR, SIGROK_FIRMWARE_PATH, SIGROKDECODE_DIR, and
SIGROKDECODE_PATH environment variables to the sigrok-cli(1) manpage.

Strictly speaking these are the libraries' environment variables, when
libsigrok looks up device firmware, and libsigrokdecode searches for
Python scripts. But the libraries don't have individual manpages. So
let's put them here for better perception, and to have them _somewhere_
and not lose this information.

diff --git a/doc/sigrok-cli.1 b/doc/sigrok-cli.1
index 47ec5792d282e43afe751de727a4009444d6eb1c..9c847a7cbe3046ef4b02998ca16ec11c711ffcaf 100644 (file)
--- a/doc/sigrok-cli.1
+++ b/doc/sigrok-cli.1
@@ -588,6 +588,25 @@ To turn on internal logging on a Lascar EL-USB series device:
 .SH "EXIT STATUS"
 .B sigrok\-cli
 exits with 0 on success, 1 on most failures.
+.SH "ENVIRONMENT"
+.TP
+.B SIGROK_FIRMWARE_DIR
+A single path where to search for firmware images, in addition to a
+builtin list of locations.
+.TP
+.B SIGROK_FIRMWARE_PATH
+Multiple path entries where to search for firmware images, in addition
+to builtin locations.
+.TP
+When decoder support was enabled in the application's configuration:
+.TP
+.B SIGROKDECODE_DIR
+A single path where to search for protocol decoders, in addition to
+a builtin list of locations.
+.TP
+.B SIGROKDECODE_PATH
+Multiple path entries where to search for protocol decoders, in addition
+to builtin locations.
 .SH "SEE ALSO"
 \fBpulseview\fP(1)
 .SH "BUGS"