package/pkgconf: add patch to restore pre-1.5.3 behavior for sysroot prefixing

Prior to the bump to version 1.5.3 in commit
4e423669399ad8389edd81761ea5c9cc26bf312d, we had a patch on pkgconf
that ensures only some variables containing paths were prefixed by the
sysroot directory when queried through pkg-config. This patch was
dropped as part of the 1.5.3 bump, but it turns out we really need
something like this, or a significant number of changes need to be
done to existing packages.

Indeed, pkg-config has no notion of which variable/path gets used at
build time vs. which variable/path gets used at runtime. Prefixing
with the sysroot the paths used at build time works and is desirable,
but prefixing the paths used at runtime doesn't work.

This commit should fix a large number of remaining build failures
related to pkgconf 1.5.3, and should allow reverting a significant
number of workarounds.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
 ...th-the-sysroot-a-subset-of-variables.patch | 142 ++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 package/pkgconf/0001-Only-prefix-with-the-sysroot-a-subset-of-variables.patch

Thomas,All,

On 2018-12-18 22:02 +0100, Thomas Petazzoni spake thusly:
> Prior to the bump to version 1.5.3 in commit
> 4e423669399ad8389edd81761ea5c9cc26bf312d, we had a patch on pkgconf
> that ensures only some variables containing paths were prefixed by the
> sysroot directory when queried through pkg-config. This patch was
> dropped as part of the 1.5.3 bump, but it turns out we really need
> something like this, or a significant number of changes need to be
> done to existing packages.
> 
> Indeed, pkg-config has no notion of which variable/path gets used at
> build time vs. which variable/path gets used at runtime. Prefixing
> with the sysroot the paths used at build time works and is desirable,
> but prefixing the paths used at runtime doesn't work.
> 
> This commit should fix a large number of remaining build failures
> related to pkgconf 1.5.3, and should allow reverting a significant
> number of workarounds.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> ---
>  ...th-the-sysroot-a-subset-of-variables.patch | 142 ++++++++++++++++++
>  1 file changed, 142 insertions(+)
>  create mode 100644 package/pkgconf/0001-Only-prefix-with-the-sysroot-a-subset-of-variables.patch
> 
> diff --git a/package/pkgconf/0001-Only-prefix-with-the-sysroot-a-subset-of-variables.patch b/package/pkgconf/0001-Only-prefix-with-the-sysroot-a-subset-of-variables.patch
> new file mode 100644
> index 0000000000..82530317a3
> --- /dev/null
> +++ b/package/pkgconf/0001-Only-prefix-with-the-sysroot-a-subset-of-variables.patch
> @@ -0,0 +1,142 @@
> +From cfefa519b40d5cfc884d1918f9fd2a4b4395aff0 Mon Sep 17 00:00:00 2001
> +From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> +Date: Sun, 16 Dec 2018 11:52:18 +0100
> +Subject: [PATCH] Only prefix with the sysroot a subset of variables
> +
> +The standard logic of pkg-config is to prefix all absolute paths by
> +the sysroot defined in PKG_CONFIG_SYSROOT_DIR. However, while some
> +paths (like includedir, libdir, and paths used in -L and -I options
> +are in this case), it is not necessarily the case for paths that are
> +used on the target.

I'm not sure I groked that last sentence correctly: if you remove the
text between parentheses, the sentence makes no sense...

> +Unfortunately, pkg-config doesn't have a sense of which path needs to
> +be prefixed by the sysroot, and which path should not be prefixed by
> +the sysroot.
> +
> +So, let's simply have a whitelist of paths that should be prefixed:
> +includedir, libdir, mapdir, pkgdatadir and sdkdir. This list of
> +variables was collected over years of Buildroot development. All other
> +paths are not prefixed by the sysroot.
> +
> +Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> +---
> + libpkgconf/tuple.c | 61 ++++++++++++++++++++++++++++++++--------------
> + 1 file changed, 43 insertions(+), 18 deletions(-)
> +
> +diff --git a/libpkgconf/tuple.c b/libpkgconf/tuple.c
> +index 8523709..6fde258 100644
> +--- a/libpkgconf/tuple.c
> ++++ b/libpkgconf/tuple.c
> +@@ -160,6 +160,18 @@ dequote(const char *value)
> + 	return buf;
> + }
> + 
> ++static char *
> ++pkgconf_tuple_parse_sysroot(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value, bool add_sysroot);
> ++
> ++const char *sysrooted_keys[] = {
> ++	"includedir",
> ++	"libdir",
> ++	"mapdir",
> ++	"pkgdatadir",
> ++	"sdkdir",
> ++	NULL,
> ++};
> ++
> + /*
> +  * !doc
> +  *
> +@@ -180,6 +192,8 @@ pkgconf_tuple_add(const pkgconf_client_t *client, pkgconf_list_t *list, const ch
> + {
> + 	char *dequote_value;
> + 	pkgconf_tuple_t *tuple = calloc(sizeof(pkgconf_tuple_t), 1);
> ++	bool add_sysroot = true;
                           ^^^^
No need to set it to true here, as...

> ++	int i;
> + 
> + 	pkgconf_tuple_find_delete(list, key);
> + 
> +@@ -187,9 +201,14 @@ pkgconf_tuple_add(const pkgconf_client_t *client, pkgconf_list_t *list, const ch
> + 
> + 	PKGCONF_TRACE(client, "adding tuple to @%p: %s => %s (parsed? %d)", list, key, dequote_value, parse);
> + 
> ++	add_sysroot = false;
                      ^^^^^
... you unconditionally override that here...

So, maybe s/true/false/ in the declaration?

Otherwise, I'm OK with the patch.

Regards,
Yann E. MORIN.

> ++	for (i = 0; sysrooted_keys[i] != NULL; i++)
> ++		if (!strcmp(key, sysrooted_keys[i]))
> ++			add_sysroot = true;
> ++
> + 	tuple->key = strdup(key);
> + 	if (parse)
> +-		tuple->value = pkgconf_tuple_parse(client, list, dequote_value);
> ++		tuple->value = pkgconf_tuple_parse_sysroot(client, list, dequote_value, add_sysroot);
> + 	else
> + 		tuple->value = strdup(dequote_value);
> + 
> +@@ -233,27 +252,14 @@ pkgconf_tuple_find(const pkgconf_client_t *client, pkgconf_list_t *list, const c
> + 	return NULL;
> + }
> + 
> +-/*
> +- * !doc
> +- *
> +- * .. c:function:: char *pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value)
> +- *
> +- *    Parse an expression for variable substitution.
> +- *
> +- *    :param pkgconf_client_t* client: The pkgconf client object to access.
> +- *    :param pkgconf_list_t* list: The variable list to search for variables (along side the global variable list).
> +- *    :param char* value: The ``key=value`` string to parse.
> +- *    :return: the variable data with any variables substituted
> +- *    :rtype: char *
> +- */
> +-char *
> +-pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value)
> ++static char *
> ++pkgconf_tuple_parse_sysroot(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value, bool add_sysroot)
> + {
> + 	char buf[PKGCONF_BUFSIZE];
> + 	const char *ptr;
> + 	char *bptr = buf;
> + 
> +-	if (*value == '/' && client->sysroot_dir != NULL && strncmp(value, client->sysroot_dir, strlen(client->sysroot_dir)))
> ++	if (add_sysroot && *value == '/' && client->sysroot_dir != NULL && strncmp(value, client->sysroot_dir, strlen(client->sysroot_dir)))
> + 		bptr += pkgconf_strlcpy(buf, client->sysroot_dir, sizeof buf);
> + 
> + 	for (ptr = value; *ptr != '\0' && bptr - buf < PKGCONF_BUFSIZE; ptr++)
> +@@ -293,7 +299,7 @@ pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const
> + 
> + 				if (kv != NULL)
> + 				{
> +-					parsekv = pkgconf_tuple_parse(client, vars, kv);
> ++					parsekv = pkgconf_tuple_parse_sysroot(client, vars, kv, add_sysroot);
> + 
> + 					strncpy(bptr, parsekv, PKGCONF_BUFSIZE - (bptr - buf));
> + 					bptr += strlen(parsekv);
> +@@ -338,6 +344,25 @@ pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const
> + 	return strdup(buf);
> + }
> + 
> ++/*
> ++ * !doc
> ++ *
> ++ * .. c:function:: char *pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value)
> ++ *
> ++ *    Parse an expression for variable substitution.
> ++ *
> ++ *    :param pkgconf_client_t* client: The pkgconf client object to access.
> ++ *    :param pkgconf_list_t* list: The variable list to search for variables (along side the global variable list).
> ++ *    :param char* value: The ``key=value`` string to parse.
> ++ *    :return: the variable data with any variables substituted
> ++ *    :rtype: char *
> ++ */
> ++char *
> ++pkgconf_tuple_parse(const pkgconf_client_t *client, pkgconf_list_t *vars, const char *value)
> ++{
> ++	return pkgconf_tuple_parse_sysroot(client, vars, value, true);
> ++}
> ++
> + /*
> +  * !doc
> +  *
> +-- 
> +2.19.2
> +
> -- 
> 2.19.2
>