Increment minor section number from 3.7.1 to 3.8.1.

Pext has nothing to do with git commit sha/date, so separate the two
sub-sections.

closes https://github.com/official-stockfish/Stockfish/pull/4785

No functional change

AUTHORS

@@ -98,6 +98,7 @@ Jake Senne (w1wwwwww)
 Jan Ondruš (hxim)
 Jared Kish (Kurtbusch, kurt22i)
 Jarrod Torriero (DU-jdto)
+Jasper Shovelton (Beanie496)
 Jean-Francois Romang (jromang)
 Jean Gauthier (OuaisBla)
 Jekaa

src/Makefile

@@ -703,24 +703,24 @@ ifeq ($(pext),yes)
 	endif
 endif
 
-### 3.7.1 Try to include git commit sha for versioning
+### 3.8.1 Try to include git commit sha for versioning
 GIT_SHA = $(shell git rev-parse HEAD 2>/dev/null | cut -c 1-8)
 ifneq ($(GIT_SHA), )
 	CXXFLAGS += -DGIT_SHA=$(GIT_SHA)
 endif
 
-### 3.7.2 Try to include git commit date for versioning
+### 3.8.2 Try to include git commit date for versioning
 GIT_DATE = $(shell git show -s --date=format:'%Y%m%d' --format=%cd HEAD 2>/dev/null)
 ifneq ($(GIT_DATE), )
 	CXXFLAGS += -DGIT_DATE=$(GIT_DATE)
 endif
 
-### 3.7.3 Try to include architecture
+### 3.8.3 Try to include architecture
 ifneq ($(ARCH), )
 	CXXFLAGS += -DARCH=$(ARCH)
 endif
 
-### 3.8 Link Time Optimization
+### 3.9 Link Time Optimization
 ### This is a mix of compile and link time options because the lto link phase
 ### needs access to the optimization flags.
 ifeq ($(optimize),yes)
@@ -755,7 +755,7 @@ ifeq ($(debug), no)
 endif
 endif
 
-### 3.9 Android 5 can only run position independent executables. Note that this
+### 3.10 Android 5 can only run position independent executables. Note that this
 ### breaks Android 4.0 and earlier.
 ifeq ($(OS), Android)
 	CXXFLAGS += -fPIE