ICU-20479 don’t leave junk in source directory on configure or make check

- see also ICU-20062
- add a `-B` option to the two python invocations on Windows
- set PYTHONDONTWRITEBYTECODE in configure.ac and icudefs.mk.in

Co-authored-by: Fredrik Roubert <roubert@google.com>

icu4c/source/configure

@@ -2603,6 +2603,10 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
+# Instruct Python to never write any byte code to the ICU source tree.
+PYTHONDONTWRITEBYTECODE=1
+export PYTHONDONTWRITEBYTECODE
+
 
 
 

icu4c/source/configure.ac

@@ -16,6 +16,10 @@ AC_INIT([ICU],
         [International Components for Unicode],
         [http://icu-project.org])
 
+# Instruct Python to never write any byte code to the ICU source tree.
+PYTHONDONTWRITEBYTECODE=1
+export PYTHONDONTWRITEBYTECODE
+
 AC_CONFIG_MACRO_DIR([config/m4])
 AC_CONFIG_SRCDIR([common/unicode/utypes.h])
 

icu4c/source/data/makedata.mak

@@ -233,7 +233,7 @@ $(TOOLS_TS): "$(ICUTOOLS)\genrb\$(CFGTOOLS)\genrb.exe" "$(ICUTOOLS)\gencnval\$(C
 
 $(COREDATA_TS):
 	@cd "$(ICUSRCDATA)"
-	py -3 -m buildtool \
+	py -3 -B -m buildtool \
 		--mode windows-exec \
 		--src_dir "$(ICUSRCDATA)" \
 		--tool_dir "$(ICUTOOLS)" \

icu4c/source/icudefs.mk.in

@@ -17,6 +17,9 @@
 
 SHELL = @SHELL@
 
+# Instruct Python to never write any byte code to the ICU source tree.
+export PYTHONDONTWRITEBYTECODE = 1
+
 # Standard directories
 
 prefix = @prefix@

icu4c/source/test/testdata/testdata.mak

@@ -35,7 +35,7 @@ CREATE_DIRS :
 "$(TESTDATAOUT)\testdata.dat" :
 	@echo Building test data
 	set PYTHONPATH=$(ICUSRCDATA);%PYTHONPATH%
-	py -3 -m buildtool \
+	py -3 -B -m buildtool \
 		--mode windows-exec \
 		--tool_dir "$(ICUTOOLS)" \
 		--tool_cfg "$(CFG)" \