package/haproxy: fix static only build

Add a patch to avoid dlfcn.h use when the toolchain is static only.

Fixes:
http://autobuild.buildroot.net/results/98caf66e8a7f72ee24e4d39f3aab541f82310369/
http://autobuild.buildroot.net/results/3024eb48a026b1a91e39f7d996be3d7f50314762/
http://autobuild.buildroot.net/results/e6bbf1469926bde9057f270940d1455e0f758e0e/

Cc: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/haproxy/0001-BUG-MEDIUM-tools-fix-build-with-static-only-toolchai.patch

@@ -0,0 +1,84 @@
+From 311df83437c4d578e35e5faca30c10da28c30323 Mon Sep 17 00:00:00 2001
+Message-Id: <311df83437c4d578e35e5faca30c10da28c30323.1595566447.git.baruch@tkos.co.il>
+From: Baruch Siach <baruch@tkos.co.il>
+Date: Fri, 24 Jul 2020 07:44:59 +0300
+Subject: [PATCH] BUG/MEDIUM: tools: fix build with static only toolchains
+
+uClibc toolchains built with no dynamic library support don't provide
+the dlfcn.h header. That leads to build failure:
+
+  CC      src/tools.o
+src/tools.c:15:10: fatal error: dlfcn.h: No such file or directory
+ #include <dlfcn.h>
+          ^~~~~~~~~
+Enable dladdr only when USE_DL is defined.
+
+Signed-off-by: Baruch Siach <baruch@tkos.co.il>
+---
+Upstream status:
+https://www.mail-archive.com/haproxy@formilux.org/msg37986.html
+
+ src/tools.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/src/tools.c b/src/tools.c
+index 1c664852ad73..0bd80f846d05 100644
+--- a/src/tools.c
++++ b/src/tools.c
+@@ -10,7 +10,7 @@
+  *
+  */
+ 
+-#ifdef __ELF__
++#if defined(__ELF__) && defined(USE_DL)
+ #define _GNU_SOURCE
+ #include <dlfcn.h>
+ #include <link.h>
+@@ -4410,7 +4410,7 @@ const char *get_exec_path()
+ 	return ret;
+ }
+ 
+-#ifdef __ELF__
++#if defined(__ELF__) && defined(USE_DL)
+ /* calls dladdr() or dladdr1() on <addr> and <dli>. If dladdr1 is available,
+  * also returns the symbol size in <size>, otherwise returns 0 there.
+  */
+@@ -4444,7 +4444,7 @@ static int dladdr_and_size(const void *addr, Dl_info *dli, size_t *size)
+  * The file name (lib or executable) is limited to what lies between the last
+  * '/' and the first following '.'. An optional prefix <pfx> is prepended before
+  * the output if not null. The file is not dumped when it's the same as the one
+- * that contains the "main" symbol, or when __ELF__ is not set.
++ * that contains the "main" symbol, or when __ELF__ && USE_DL are not set.
+  *
+  * The symbol's base address is returned, or NULL when unresolved, in order to
+  * allow the caller to match it against known ones.
+@@ -4472,7 +4472,7 @@ const void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
+ #endif
+ 	};
+ 
+-#ifdef __ELF__
++#if defined(__ELF__) && defined(USE_DL)
+ 	Dl_info dli, dli_main;
+ 	size_t size;
+ 	const char *fname, *p;
+@@ -4489,7 +4489,7 @@ const void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
+ 		}
+ 	}
+ 
+-#ifdef __ELF__
++#if defined(__ELF__) && defined(USE_DL)
+ 	/* Now let's try to be smarter */
+ 	if (!dladdr_and_size(addr, &dli, &size))
+ 		goto unknown;
+@@ -4529,7 +4529,7 @@ const void *resolve_sym_name(struct buffer *buf, const char *pfx, void *addr)
+ 		chunk_appendf(buf, "+%#lx", (long)(addr - dli.dli_fbase));
+ 		return NULL;
+ 	}
+-#endif /* __ELF__ */
++#endif /* __ELF__ && USE_DL */
+  unknown:
+ 	/* unresolved symbol from the main file, report relative offset to main */
+ 	if ((void*)addr < (void*)main)
+-- 
+2.27.0
+