diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 753763fa..da292845 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -119,7 +119,9 @@ jobs:
         run: |
           mkdir build
           pushd build
-          cmake -G"Unix Makefiles" -DWITH_12BIT=1 ..
+          cmake -G"Unix Makefiles" -DWITH_12BIT=1 \
+            -DCMAKE_C_FLAGS='--std=gnu90 -Wall -Werror -Wextra -Wpedantic -pedantic-errors -Wdouble-promotion -Wformat-overflow=2 -Wformat-security -Wformat-signedness -Wformat-truncation=2 -Wformat-y2k -Wmissing-include-dirs -Wshift-overflow=2 -Wswitch-bool -Wno-unused-parameter -Wuninitialized -Wstrict-overflow=2 -Wstringop-overflow=4 -Wstringop-truncation -Wduplicated-branches -Wduplicated-cond -Wdeclaration-after-statement -Wshadow -Wunsafe-loop-optimizations -Wundef -Wcast-align -Wno-clobbered -Wjump-misses-init -Wno-sign-compare -Wlogical-op -Waggregate-return -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Wpacked -Wredundant-decls -Wnested-externs -Winline -Wno-long-long -Wdisabled-optimization -Wno-overlength-strings' \
+            ..
           export NUMCPUS=`grep -c '^processor' /proc/cpuinfo`
           make -j$NUMCPUS --load-average=$NUMCPUS
           make test
@@ -139,7 +141,9 @@ jobs:
         run: |
           mkdir build
           pushd build
-          cmake -G"Unix Makefiles" -DWITH_JPEG7=1 -DCMAKE_C_FLAGS=-mx32 ..
+          cmake -G"Unix Makefiles" -DWITH_JPEG7=1 -DCMAKE_C_FLAGS=-mx32 \
+            -DCMAKE_C_FLAGS='--std=gnu90 -Wall -Werror -Wextra -Wpedantic -pedantic-errors -Wdouble-promotion -Wformat-overflow=2 -Wformat-security -Wformat-signedness -Wformat-truncation=2 -Wformat-y2k -Wmissing-include-dirs -Wshift-overflow=2 -Wswitch-bool -Wno-unused-parameter -Wuninitialized -Wstrict-overflow=2 -Wstringop-overflow=4 -Wstringop-truncation -Wduplicated-branches -Wduplicated-cond -Wdeclaration-after-statement -Wshadow -Wunsafe-loop-optimizations -Wundef -Wcast-align -Wno-clobbered -Wjump-misses-init -Wno-sign-compare -Wlogical-op -Waggregate-return -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Wpacked -Wredundant-decls -Wnested-externs -Winline -Wno-long-long -Wdisabled-optimization -Wno-overlength-strings' \
+            ..
           export NUMCPUS=`grep -c '^processor' /proc/cpuinfo`
           make -j$NUMCPUS --load-average=$NUMCPUS
           make test
@@ -161,7 +165,9 @@ jobs:
         run: |
           mkdir build
           pushd build
-          cmake -G"Unix Makefiles" -DWITH_JPEG8=1 ..
+          cmake -G"Unix Makefiles" -DWITH_JPEG8=1 \
+            -DCMAKE_C_FLAGS='--std=gnu90 -Wall -Werror -Wextra -Wpedantic -pedantic-errors -Wdouble-promotion -Wformat-overflow=2 -Wformat-security -Wformat-signedness -Wformat-truncation=2 -Wformat-y2k -Wmissing-include-dirs -Wshift-overflow=2 -Wswitch-bool -Wno-unused-parameter -Wuninitialized -Wstrict-overflow=2 -Wstringop-overflow=4 -Wstringop-truncation -Wduplicated-branches -Wduplicated-cond -Wdeclaration-after-statement -Wshadow -Wunsafe-loop-optimizations -Wundef -Wcast-align -Wno-clobbered -Wjump-misses-init -Wno-sign-compare -Wlogical-op -Waggregate-return -Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-declarations -Wpacked -Wredundant-decls -Wnested-externs -Winline -Wno-long-long -Wdisabled-optimization -Wno-overlength-strings' \
+            ..
           export NUMCPUS=`grep -c '^processor' /proc/cpuinfo`
           make -j$NUMCPUS --load-average=$NUMCPUS
           make test
diff --git a/cdjpeg.c b/cdjpeg.c
index 5278c1db..304a6650 100644
--- a/cdjpeg.c
+++ b/cdjpeg.c
@@ -4,7 +4,7 @@
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1991-1997, Thomas G. Lane.
  * libjpeg-turbo Modifications:
- * Copyright (C) 2019, D. R. Commander.
+ * Copyright (C) 2019, 2022, D. R. Commander.
  * For conditions of distribution and use, see the accompanying README.ijg
  * file.
  *
@@ -34,7 +34,7 @@ progress_monitor(j_common_ptr cinfo)
     int scan_no = ((j_decompress_ptr)cinfo)->input_scan_number;
 
     if (scan_no > (int)prog->max_scans) {
-      fprintf(stderr, "Scan number %d exceeds maximum scans (%d)\n", scan_no,
+      fprintf(stderr, "Scan number %d exceeds maximum scans (%u)\n", scan_no,
               prog->max_scans);
       exit(EXIT_FAILURE);
     }
diff --git a/djpeg.c b/djpeg.c
index d02a2183..b30a5e43 100644
--- a/djpeg.c
+++ b/djpeg.c
@@ -5,7 +5,7 @@
  * Copyright (C) 1991-1997, Thomas G. Lane.
  * Modified 2013-2019 by Guido Vollbeding.
  * libjpeg-turbo Modifications:
- * Copyright (C) 2010-2011, 2013-2017, 2019-2020, D. R. Commander.
+ * Copyright (C) 2010-2011, 2013-2017, 2019-2020, 2022, D. R. Commander.
  * Copyright (C) 2015, Google, Inc.
  * For conditions of distribution and use, see the accompanying README.ijg
  * file.
@@ -717,7 +717,7 @@ main(int argc, char **argv)
      * that skip_start <= skip_end.
      */
     if (skip_end > cinfo.output_height - 1) {
-      fprintf(stderr, "%s: skip region exceeds image height %d\n", progname,
+      fprintf(stderr, "%s: skip region exceeds image height %u\n", progname,
               cinfo.output_height);
       exit(EXIT_FAILURE);
     }
@@ -738,7 +738,7 @@ main(int argc, char **argv)
     }
     if ((tmp = jpeg_skip_scanlines(&cinfo, skip_end - skip_start + 1)) !=
         skip_end - skip_start + 1) {
-      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %d rather than %d\n",
+      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %u rather than %u\n",
               progname, tmp, skip_end - skip_start + 1);
       exit(EXIT_FAILURE);
     }
@@ -757,7 +757,7 @@ main(int argc, char **argv)
      */
     if (crop_x + crop_width > cinfo.output_width ||
         crop_y + crop_height > cinfo.output_height) {
-      fprintf(stderr, "%s: crop dimensions exceed image dimensions %d x %d\n",
+      fprintf(stderr, "%s: crop dimensions exceed image dimensions %u x %u\n",
               progname, cinfo.output_width, cinfo.output_height);
       exit(EXIT_FAILURE);
     }
@@ -778,7 +778,7 @@ main(int argc, char **argv)
 
     /* Process data */
     if ((tmp = jpeg_skip_scanlines(&cinfo, crop_y)) != crop_y) {
-      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %d rather than %d\n",
+      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %u rather than %u\n",
               progname, tmp, crop_y);
       exit(EXIT_FAILURE);
     }
@@ -791,7 +791,7 @@ main(int argc, char **argv)
          jpeg_skip_scanlines(&cinfo,
                              cinfo.output_height - crop_y - crop_height)) !=
         cinfo.output_height - crop_y - crop_height) {
-      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %d rather than %d\n",
+      fprintf(stderr, "%s: jpeg_skip_scanlines() returned %u rather than %u\n",
               progname, tmp, cinfo.output_height - crop_y - crop_height);
       exit(EXIT_FAILURE);
     }
diff --git a/rdjpgcom.c b/rdjpgcom.c
index 76736d74..fc0c08c0 100644
--- a/rdjpgcom.c
+++ b/rdjpgcom.c
@@ -4,8 +4,8 @@
  * This file was part of the Independent JPEG Group's software:
  * Copyright (C) 1994-1997, Thomas G. Lane.
  * Modified 2009 by Bill Allombert, Guido Vollbeding.
- * It was modified by The libjpeg-turbo Project to include only code relevant
- * to libjpeg-turbo.
+ * libjpeg-turbo Modifications:
+ * Copyright (C) 2022, D. R. Commander.
  * For conditions of distribution and use, see the accompanying README.ijg
  * file.
  *
@@ -249,7 +249,7 @@ process_COM(int raw)
     } else if (isprint(ch)) {
       putc(ch, stdout);
     } else {
-      printf("\\%03o", ch);
+      printf("\\%03o", (unsigned int)ch);
     }
     lastch = ch;
     length--;
diff --git a/rdppm.c b/rdppm.c
index cd6f9a4e..439eefb6 100644
--- a/rdppm.c
+++ b/rdppm.c
@@ -181,13 +181,13 @@ get_text_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
       GRAY_RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),
                          ptr[aindex] = 0xFF;)
     else
-      GRAY_RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),)
+      GRAY_RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval), {})
   } else {
     if (aindex >= 0)
       GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],
                          ptr[aindex] = 0xFF;)
     else
-      GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],)
+      GRAY_RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)], {})
   }
   return 1;
 }
@@ -255,13 +255,13 @@ get_text_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
       RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),
                     ptr[aindex] = 0xFF;)
     else
-      RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval),)
+      RGB_READ_LOOP(read_pbm_integer(cinfo, infile, maxval), {})
   } else {
     if (aindex >= 0)
       RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],
                     ptr[aindex] = 0xFF;)
     else
-      RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)],)
+      RGB_READ_LOOP(rescale[read_pbm_integer(cinfo, infile, maxval)], {})
   }
   return 1;
 }
@@ -347,12 +347,12 @@ get_gray_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
     if (aindex >= 0)
       GRAY_RGB_READ_LOOP(*bufferptr++, ptr[aindex] = 0xFF;)
     else
-      GRAY_RGB_READ_LOOP(*bufferptr++,)
+      GRAY_RGB_READ_LOOP(*bufferptr++, {})
   } else {
     if (aindex >= 0)
       GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)], ptr[aindex] = 0xFF;)
     else
-      GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)],)
+      GRAY_RGB_READ_LOOP(rescale[UCH(*bufferptr++)], {})
   }
   return 1;
 }
@@ -415,12 +415,12 @@ get_rgb_row(j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
     if (aindex >= 0)
       RGB_READ_LOOP(*bufferptr++, ptr[aindex] = 0xFF;)
     else
-      RGB_READ_LOOP(*bufferptr++,)
+      RGB_READ_LOOP(*bufferptr++, {})
   } else {
     if (aindex >= 0)
       RGB_READ_LOOP(rescale[UCH(*bufferptr++)], ptr[aindex] = 0xFF;)
     else
-      RGB_READ_LOOP(rescale[UCH(*bufferptr++)],)
+      RGB_READ_LOOP(rescale[UCH(*bufferptr++)], {})
   }
   return 1;
 }
diff --git a/turbojpeg.c b/turbojpeg.c
index a6888a20..d780dc25 100644
--- a/turbojpeg.c
+++ b/turbojpeg.c
@@ -2010,13 +2010,13 @@ DLLEXPORT int tjTransform(tjhandle handle, const unsigned char *jpegBuf,
 
       for (ci = 0; ci < cinfo->num_components; ci++) {
         jpeg_component_info *compptr = &cinfo->comp_info[ci];
-        tjregion arrayRegion = {
-          0, 0, compptr->width_in_blocks * DCTSIZE, DCTSIZE
-        };
-        tjregion planeRegion = {
-          0, 0, compptr->width_in_blocks * DCTSIZE,
-          compptr->height_in_blocks * DCTSIZE
-        };
+        tjregion arrayRegion = { 0, 0, 0, 0 };
+        tjregion planeRegion = { 0, 0, 0, 0 };
+
+        arrayRegion.w = compptr->width_in_blocks * DCTSIZE;
+        arrayRegion.h = DCTSIZE;
+        planeRegion.w = compptr->width_in_blocks * DCTSIZE;
+        planeRegion.h = compptr->height_in_blocks * DCTSIZE;
 
         for (by = 0; by < compptr->height_in_blocks;
              by += compptr->v_samp_factor) {