Faster gamma calculation #1032

Job	Run time
ruby-versions / Generate Ruby versions	4s
ubuntu-latest 2.7	1m 25s
macos-latest 3.3	41s
macos-latest head	32s
ubuntu-latest 3.0	51s
macos-14 3.0	36s
ubuntu-latest 3.4	52s
ubuntu-latest 3.3	56s
macos-latest 3.0	31s
macos-latest debug	34s
macos-latest 2.7	1m 7s
ubuntu-latest 3.2	55s
macos-latest 4.0	29s
macos-latest 3.4	31s
macos-latest 3.2	35s
macos-14 3.2	30s
macos-latest 3.1	39s
macos-14 2.7	1m 7s
ubuntu-latest 3.1	51s
ubuntu-latest head	44s
macos-14 4.0	31s
ubuntu-latest 4.0	45s
macos-14 3.3	30s
windows-latest mswin	2m 5s
macos-14 3.4	28s
ubuntu-latest debug	49s
macos-14 3.1	34s
windows-latest head	2m 48s
windows-latest mingw	3m 9s
windows-latest 3.4	2m 56s
macos-14 debug	34s
windows-latest 2.7	5m 19s
macos-14 head	27s
windows-latest 4.0	3m 18s
windows-latest 3.3	3m 27s
	42m 10s

Provide feedback