Clarify and simplify strings to help translators

Closes: #604914

Suggested-by: Andrei Popescu <andreimpopescu@gmail.com>
Signed-off-by: Guillem Jover <guillem@debian.org>

debian/changelog

@@ -14,6 +14,7 @@ dpkg (1.16.0) UNRELEASED; urgency=low
   * Add missing space in update-alternative --set-selections output.
   * Add missing options to update-alternative --help output.
   * Count “conffile name is duplicated” for dpkg-deb warning count summary.
+  * Improve and clarify strings for translation. Closes: #604914
 
   [ Raphaël Hertzog ]
   * Fail properly when debian/source/format is empty. Closes: #600854

lib/dpkg/ehandle.c

@@ -119,7 +119,7 @@ error_context_new(void)
 
   necp = malloc(sizeof(struct error_context));
   if (!necp)
-    ohshite(_("out of memory pushing error handler"));
+    ohshite(_("out of memory for new error context"));
   necp->next= econtext;
   necp->cleanups= NULL;
   econtext= necp;

lib/dpkg/parsehelp.c

@@ -131,7 +131,8 @@ pkg_name_is_illegal(const char *p, const char **ep)
   int c;
 
   if (!*p) return _("may not be empty string");
-  if (!isalnum(*p)) return _("must start with an alphanumeric");
+  if (!isalnum(*p))
+    return _("must start with an alphanumeric character");
   while ((c = *p++) != '\0')
     if (!isalnum(c) && !strchr(alsoallowed,c)) break;
   if (!c) return NULL;

src/help.c

@@ -136,12 +136,11 @@ void checkpath(void) {
 
   if (warned)
     forcibleerr(fc_badpath,
-                P_("%d expected program not found in PATH or not executable.\n"
-                   "NB: root's PATH should usually contain "
-                   "/usr/local/sbin, /usr/sbin and /sbin.",
-                   "%d expected programs not found in PATH or not executable.\n"
-                   "NB: root's PATH should usually contain "
-                   "/usr/local/sbin, /usr/sbin and /sbin.", warned), warned);
+                P_("%d expected program not found in PATH or not executable.\n%s",
+                   "%d expected programs not found in PATH or not executable.\n%s",
+                   warned),
+                warned, _("Note: root's PATH should usually contain "
+                          "/usr/local/sbin, /usr/sbin and /sbin."));
 }
 
 bool