build: Disable LERC in libTIFF local build script

[lji-ilm]

Description

Recently, when building OIIO using OpenImageIO_BUILD_LOCAL_DEPS=all cmake option, I noticed a reference to lerc that fails during the linker stage, when compiling the simd tests:

[ 71%] Building CXX object src/libutil/CMakeFiles/simd_test.dir/simd_test.cpp.o
[ 71%] Linking CXX executable ../../bin/simd_test
/usr/bin/ld: ../../lib/libOpenImageIO.so.3.1.7: undefined reference to `lerc_decode'
/usr/bin/ld: ../../lib/libOpenImageIO.so.3.1.7: undefined reference to `lerc_encodeForVersion'
/usr/bin/ld: ../../lib/libOpenImageIO.so.3.1.7: undefined reference to `lerc_getBlobInfo'
collect2: error: ld returned 1 exit status
gmake[2]: *** [src/libutil/CMakeFiles/simd_test.dir/build.make:100: bin/simd_test] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:2158: src/libutil/CMakeFiles/simd_test.dir/all] Error 2
gmake: *** [Makefile:166: all] Error 2

lerc is an image compression library from ESRI: https://github.com/Esri/lerc

A deeper dive of this reference to lerc shows that it is referred in libtiff. libtiff, however, did not seem to correctly export this dependency to OIIO when being built locally.

If someone was building OIIO with a system-installed libtiff, this error is unlikely to happen.

By disabling lerc in libTiff, the local build scripts ( OpenImageIO_BUILD_LOCAL_DEPS=all ) runs without a problem.

Tests

Tested build OIIO with OpenImageIO_BUILD_LOCAL_DEPS=all with this patch and was successful in finishing the build.

Checklist:

• I have read the contribution guidelines.
• I have updated the documentation, if applicable. (Check if there is no
  need to update the documentation, for example if this is a bug fix that
  doesn't change the API.)
• I have ensured that the change is tested somewhere in the testsuite
  (adding new test cases if necessary).
• If I added or modified a C++ API call, I have also amended the
  corresponding Python bindings (and if altering ImageBufAlgo functions, also
  exposed the new functionality as oiiotool options).
• My code follows the prevailing code style of this project. If I haven't
  already run clang-format before submitting, I definitely will look at the CI
  test that runs clang-format and fix anything that it highlights as being
  nonconforming.

[lgritz]

The icx/icc failures are unrelated to your changes.