cderror.h: Always include all img I/O err messages

The 8-bit-per-sample image I/O modules have always been built with BMP,
GIF, PBMPLUS, and Targa support, and the 12-bit-per-sample image I/O
modules have always been built with only GIF and PBMPLUS support.  In
libjpeg-turbo 2.1.x and prior, cjpeg and djpeg were built with the same
image format support as the image I/O modules.  However, because of the
multi-precision feature introduced in libjpeg-turbo 3.0.x, cjpeg and
djpeg are now always built with support for all image formats.  Thus,
the error message table compiled into cjpeg and djpeg was a superset of
the error message table compiled into the 12-bit-per-sample and
16-bit-per-sample image I/O modules.  If, for example, the
12-bit-per-sample PPM writer threw JERR_PPM_COLORSPACE (== 15, because
it was built with only GIF and PBMPLUS support), then djpeg interpreted
that as JERR_GIF_COLORSPACE (== 15, because it was built with support
for all image formats.)  There was no chance of a buffer overrun, since
the error message table lookup was performed against the table compiled
into cjpeg and djpeg, which contained all possible entries.  However,
this issue caused an incorrect error message to be displayed by cjpeg or
djpeg if a 12-bit-per-sample or 16-bit-per-sample image I/O module threw
an error.  This commit simply removes the *_SUPPORTED #ifdefs from
cderror.h so that all image I/O error messages are always included in
every instance of the image I/O error message table.

Note that a similar issue could have also occurred with the
12-bit-per-sample and 16-bit-per-sample TurboJPEG image I/O functions,
since the 12-bit-per-sample and 16-bit-per-sample image I/O modules
supporting those functions are built with only PBMPLUS support whereas
the library as a whole is built with BMP and PBMPLUS support.

cderror.h

@@ -42,7 +42,6 @@ typedef enum {
 
 JMESSAGE(JMSG_FIRSTADDONCODE = 1000, NULL) /* Must be first entry! */
 
-#ifdef BMP_SUPPORTED
 JMESSAGE(JERR_BMP_BADCMAP, "Unsupported BMP colormap format")
 JMESSAGE(JERR_BMP_BADDEPTH, "Only 8-, 24-, and 32-bit BMP files are supported")
 JMESSAGE(JERR_BMP_BADHEADER, "Invalid BMP file: bad header length")
@@ -56,9 +55,7 @@ JMESSAGE(JTRC_BMP, "%ux%u %d-bit BMP image")
 JMESSAGE(JTRC_BMP_MAPPED, "%ux%u 8-bit colormapped BMP image")
 JMESSAGE(JTRC_BMP_OS2, "%ux%u %d-bit OS2 BMP image")
 JMESSAGE(JTRC_BMP_OS2_MAPPED, "%ux%u 8-bit colormapped OS2 BMP image")
-#endif /* BMP_SUPPORTED */
 
-#ifdef GIF_SUPPORTED
 JMESSAGE(JERR_GIF_BUG, "GIF output got confused")
 JMESSAGE(JERR_GIF_CODESIZE, "Bogus GIF codesize %d")
 JMESSAGE(JERR_GIF_COLORSPACE, "GIF output must be grayscale or RGB")
@@ -74,9 +71,7 @@ JMESSAGE(JWRN_GIF_BADDATA, "Corrupt data in GIF file")
 JMESSAGE(JWRN_GIF_CHAR, "Bogus char 0x%02x in GIF file, ignoring")
 JMESSAGE(JWRN_GIF_ENDCODE, "Premature end of GIF image")
 JMESSAGE(JWRN_GIF_NOMOREDATA, "Ran out of GIF bits")
-#endif /* GIF_SUPPORTED */
 
-#ifdef PPM_SUPPORTED
 JMESSAGE(JERR_PPM_COLORSPACE, "PPM output must be grayscale or RGB")
 JMESSAGE(JERR_PPM_NONNUMERIC, "Nonnumeric data in PPM file")
 JMESSAGE(JERR_PPM_NOT, "Not a PPM/PGM file")
@@ -85,18 +80,14 @@ JMESSAGE(JTRC_PGM, "%ux%u PGM image")
 JMESSAGE(JTRC_PGM_TEXT, "%ux%u text PGM image")
 JMESSAGE(JTRC_PPM, "%ux%u PPM image")
 JMESSAGE(JTRC_PPM_TEXT, "%ux%u text PPM image")
-#endif /* PPM_SUPPORTED */
 
-#ifdef TARGA_SUPPORTED
 JMESSAGE(JERR_TGA_BADCMAP, "Unsupported Targa colormap format")
 JMESSAGE(JERR_TGA_BADPARMS, "Invalid or unsupported Targa file")
 JMESSAGE(JERR_TGA_COLORSPACE, "Targa output must be grayscale or RGB")
 JMESSAGE(JTRC_TGA, "%ux%u RGB Targa image")
 JMESSAGE(JTRC_TGA_GRAY, "%ux%u grayscale Targa image")
 JMESSAGE(JTRC_TGA_MAPPED, "%ux%u colormapped Targa image")
-#else
 JMESSAGE(JERR_TGA_NOTCOMP, "Targa support was not compiled")
-#endif /* TARGA_SUPPORTED */
 
 JMESSAGE(JERR_BAD_CMAP_FILE,
          "Color map file is invalid or of unsupported format")