Add -workers option to use all cores.

.github/workflows/on_PR_linux_fuzz.yml

@@ -27,4 +27,4 @@ jobs:
       run: |
         cd build
         mkdir corpus
-        ./bin/fuzz-read-print-write corpus ../test/data/ -jobs=$(nproc) -max_total_time=60 -max_len=4096
+        ./bin/fuzz-read-print-write corpus ../test/data/ -jobs=$(nproc) -workers=$(nproc) -max_total_time=120 -max_len=4096

README.md

@@ -1056,11 +1056,12 @@ $ cmake .. -DCMAKE_CXX_COMPILER=$(which clang++) -DEXIV2_BUILD_FUZZ_TESTS=ON -DE
 $ cmake --build .
 ```
 
-To execute the fuzzers:
+To execute a fuzzer:
 
 ```bash
 cd <exiv2dir>/build-fuzz
-bin/<fuzzer_name> # for example ./bin/read-metadata.cpp
+mkdir corpus
+./bin/fuzz-read-print-write corpus ../test/data/ -jobs=$(nproc) -workers=$(nproc) -max_len=4096
 ```
 
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