client/cmd_line_parser: fix wrong reporting of bad argument in --bla=val case

We use get_opt_long, which allows non ambiguous abbreviations, but
since we didn't like that we have code that checks for abbreviations and
issues an error. But that code only handled separate argument and key like:
--bla value
and didn't handle them in the same arguemnts, like:
--bla=value
This patch fixes that, and gives a slightly better error report (it still
contains the =value part though)

1 files changed, 5 insertions, 2 deletions

diff --git a/client/cmd_line_parser.cpp b/client/cmd_line_parser.cpp
index 963250b1..da4af05a 100644
--- a/client/cmd_line_parser.cpp
+++ b/client/cmd_line_parser.cpp
@@ -346,10 +346,13 @@ int CmdLineParser::get_option(char** val)
         }
 
 #ifdef DISABLE_ABBREVIATE
-        int name_pos = (opt_obj->type == REQUIRED_ARGUMENT) ? optind - 2 : optind - 1;
+        int name_pos =
+            (opt_obj->type == REQUIRED_ARGUMENT && optarg[-1] != '=')
+            ? optind - 2
+            : optind - 1;
         std::string cmd_name(_argv[name_pos] + 2);
         if (cmd_name.find(opt_obj->name) != 0) {
-            Platform::term_printf("%s: invalid option '--%s'\n", _argv[0], cmd_name.c_str());
+            Platform::term_printf("%s: invalid abbreviated option '--%s'\n", _argv[0], cmd_name.c_str());
             return OPTION_ERROR;
         }
 #endif