[source] opkg: disable the use of vfork for the host build

[LEDE Commits]

nbd pushed a commit to source.git, branch master:
https://git.lede-project.org/02e3c718e9ad0c14aa3cf359ba2a4763e81df805

commit 02e3c718e9ad0c14aa3cf359ba2a4763e81df805
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Sun Aug 28 14:33:48 2016 +0200

    opkg: disable the use of vfork for the host build
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 package/system/opkg/Makefile                    |  2 +-
 package/system/opkg/patches/280-use-vfork.patch | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/package/system/opkg/Makefile b/package/system/opkg/Makefile
index 67ceb7c..446463e 100644
--- a/package/system/opkg/Makefile
+++ b/package/system/opkg/Makefile
@@ -109,7 +109,7 @@ endef
 
 Package/opkg-smime/conffiles = $(Package/opkg/conffiles)
 
-TARGET_CFLAGS += -ffunction-sections -fdata-sections
+TARGET_CFLAGS += -ffunction-sections -fdata-sections -DOPKG_USE_VFORK=1
 EXTRA_CFLAGS += $(TARGET_CPPFLAGS)
 
 CONFIGURE_ARGS += \
diff --git a/package/system/opkg/patches/280-use-vfork.patch b/package/system/opkg/patches/280-use-vfork.patch
index 1c46f52..fc6058a 100644
--- a/package/system/opkg/patches/280-use-vfork.patch
+++ b/package/system/opkg/patches/280-use-vfork.patch
@@ -1,20 +1,25 @@
 --- a/libbb/gz_open.c
 +++ b/libbb/gz_open.c
-@@ -29,7 +29,7 @@
+@@ -29,7 +29,12 @@
  #include <unistd.h>
  #include "libbb.h"
  
--static int gz_use_vfork;
-+static const int gz_use_vfork = 1;
++#ifdef OPKG_USE_VFORK
++static const int gz_use_vfork = OPKG_USE_VFORK;
++#else
+ static int gz_use_vfork;
++#endif
++
  
  FILE *
  gz_open(FILE *compressed_file, int *pid)
-@@ -38,8 +38,6 @@ gz_open(FILE *compressed_file, int *pid)
+@@ -38,7 +43,9 @@ gz_open(FILE *compressed_file, int *pid)
  	off_t floc;
  	int cfile = -1;
  
--	gz_use_vfork = (getenv("OPKG_USE_VFORK") != NULL);
--
++#ifndef OPKG_USE_VFORK
+ 	gz_use_vfork = (getenv("OPKG_USE_VFORK") != NULL);
++#endif
+ 
  	if (gz_use_vfork) {
  		/* Create a new file descriptor for the input stream
- 		 * (it *must* be associated with a file), and lseek()