[DO-972][DO-980] add freetype and pkgconf recipes (!6)

Co-authored-by: aleksandr.vodyanov <aleksandr.vodyanov@avroid.tech>
Reviewed-on: https://git.avroid.tech/Conan/conan_build/pulls/6

recipes/pkgconf/all/test_package/src/CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.15)
+project(test_package LANGUAGES C)
+
+find_package(pkgconf REQUIRED)
+add_executable(${PROJECT_NAME} test_package.c)
+target_link_libraries(${PROJECT_NAME} PRIVATE pkgconf::pkgconf)

recipes/pkgconf/all/test_package/src/libexample1.pc

@@ -0,0 +1,6 @@
+Name: libexample1
+Description: This is a description of libexample1.
+Requires:
+Version: 0.42
+Libs: -L/usr/lib -lexample1
+Cflags:  -I/usr/include/libexample1 -I/usr/include -DEXAMPLE1_STATIC

recipes/pkgconf/all/test_package/src/test_package.c

@@ -0,0 +1,24 @@
+#include "libpkgconf/libpkgconf.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool error_callback(const char *msg, const pkgconf_client_t *client, const void *data) {
+    printf("error callback: %s\n", msg);
+    fflush(stdout);
+    return 1; // 1/true means message handled
+}
+
+int main() {
+    pkgconf_client_t client;
+    memset(&client, 0, sizeof(client));
+
+    pkgconf_client_init(&client, error_callback, NULL, pkgconf_cross_personality_default());
+
+    pkgconf_error(&client, "%s:%d %s: %s", __FILE__, __LINE__, __FUNCTION__, "test error");
+
+    pkgconf_client_deinit(&client);
+
+    return 0;
+}