Compile ffmpeg-4.2.2 on macOS with Haivision-SRT 1.4.1 >>> ERROR: srt >= 1.3.0 not found using pkg-config

I got following error while compiling ffmpeg-4.2.2 on macOS 10.14.6 with the Haivision-SRT 1.4.1 package:

ERROR: srt >= 1.3.0 not found using pkg-config

First I tried it with the srt package from Homebrew and then I compiled it from source. But both times I got the same error.
I compiled the same ffmpeg 4.2.2 package on Ubuntu with SRT 1.4.1 without problems.

From the ffbuild/config.log:

require_pkg_config libsrt srt >= 1.3.0 srt/srt.h srt_socket
check_pkg_config libsrt srt >= 1.3.0 srt/srt.h srt_socket
test_pkg_config libsrt srt >= 1.3.0 srt/srt.h srt_socket
false –exists –print-errors srt >= 1.3.0
ERROR: srt >= 1.3.0 not found using pkg-config

Why is it asking for such an old libsrt version? From where does it get this requirement?

Thank you.