Upstream-Status: Backport [767e0316450911f1158bd4f7fd8dcd066bae5c55]
Signed-off-by: Ross Burton <ross.burton@arm.com>

From 0ce0a85597db48a2fca619bd95e34af091e54ae8 Mon Sep 17 00:00:00 2001
From: Ross Burton <ross.burton@arm.com>
Date: Thu, 22 Jul 2021 16:31:11 +0100
Subject: [PATCH] Fix build race in Makefile

The current rule for the binaries is:

glew.bin: glew.lib bin bin/$(GLEWINFO.BIN) bin/$(VISUALINFO.BIN)

In parallel builds, all of those targets happen at the same time. This
means that 'bin' can happen *after* 'bin/$(GLEWINFO.BIN)', which is a
problem as the 'bin' target's responsibility is to create the directory
that the other target writes into.

Solve this by not having a separate 'create directory' target which is
fundamentally racy, and simply mkdir in each target which writes into it.
---
 Makefile | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index d0e4614..04af44c 100644
--- a/Makefile
+++ b/Makefile
@@ -171,21 +171,20 @@ VISUALINFO.BIN.OBJ := $(VISUALINFO.BIN.OBJ:.c=.o)
 # Don't build glewinfo or visualinfo for NaCL, yet.
 
 ifneq ($(filter nacl%,$(SYSTEM)),)
-glew.bin: glew.lib bin
+glew.bin: glew.lib
 else
-glew.bin: glew.lib bin bin/$(GLEWINFO.BIN) bin/$(VISUALINFO.BIN) 
+glew.bin: glew.lib bin/$(GLEWINFO.BIN) bin/$(VISUALINFO.BIN)
 endif
 
-bin:
-	mkdir bin
-
 bin/$(GLEWINFO.BIN): $(GLEWINFO.BIN.OBJ) $(LIB.SHARED.DIR)/$(LIB.SHARED)
+	@mkdir -p $(dir $@)
 	$(CC) $(CFLAGS) -o $@ $(GLEWINFO.BIN.OBJ) $(BIN.LIBS)
 ifneq ($(STRIP),)
 	$(STRIP) -x $@
 endif
 
 bin/$(VISUALINFO.BIN): $(VISUALINFO.BIN.OBJ) $(LIB.SHARED.DIR)/$(LIB.SHARED)
+	@mkdir -p $(dir $@)
 	$(CC) $(CFLAGS) -o $@ $(VISUALINFO.BIN.OBJ) $(BIN.LIBS)
 ifneq ($(STRIP),)
 	$(STRIP) -x $@
-- 
2.25.1