Fix signed/unsigned comparison warnings in core.

library/Console-posix.cpp

@@ -635,7 +635,7 @@ namespace DFHack
                     prompt_refresh();
                     break;
                 case 11: // Ctrl+k, delete from current to end of line.
-                    if (raw_cursor < raw_buffer.size())
+                    if (size_t(raw_cursor) < raw_buffer.size())
                         yank_buffer = raw_buffer.substr(raw_cursor);
                     raw_buffer.erase(raw_cursor);
                     prompt_refresh();
@@ -651,7 +651,7 @@ namespace DFHack
                 case 20: // Ctrl+t, transpose current and previous characters
                     if (raw_buffer.size() >= 2 && raw_cursor > 0)
                     {
-                        if (raw_cursor == raw_buffer.size())
+                        if (size_t(raw_cursor) == raw_buffer.size())
                             raw_cursor--;
                         std::swap(raw_buffer[raw_cursor - 1], raw_buffer[raw_cursor]);
                         raw_cursor++;

library/modules/Job.cpp

@@ -508,7 +508,7 @@ bool DFHack::Job::removePostings(df::job *job, bool remove_all)
     bool removed = false;
     if (!remove_all)
     {
-        if (job->posting_index >= 0 && job->posting_index < world->jobs.postings.size())
+        if (job->posting_index >= 0 && size_t(job->posting_index) < world->jobs.postings.size())
         {
             world->jobs.postings[job->posting_index]->flags.bits.dead = true;
             removed = true;

library/modules/Screen.cpp

@@ -511,8 +511,8 @@ void PenArray::draw(unsigned int x, unsigned int y, unsigned int width, unsigned
     {
         for (unsigned int gridy = y; gridy < y + height; gridy++)
         {
-            if (gridx >= gps->dimx ||
+            if (gridx >= unsigned(gps->dimx) ||
-                gridy >= gps->dimy ||
+                gridy >= unsigned(gps->dimy) ||
                 gridx - x + bufx >= dimx ||
                 gridy - y + bufy >= dimy)
                 continue;