package/valijson: drop boost dependency

boost is not mandatory since the deactivation of tests when bumping to
version 0.2.0 in commit d8e2876104be3f9f01613b17d3e60120883be1a1 and
https://github.com/tristanpenman/valijson/commit/1844241d2a2379bca79a0d654f4b007209b10883

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/valijson/Config.in

@@ -1,10 +1,6 @@
 config BR2_PACKAGE_VALIJSON
 	bool "valijson"
-	depends on BR2_USE_WCHAR
 	depends on BR2_INSTALL_LIBSTDCPP
-	depends on BR2_TOOLCHAIN_HAS_THREADS
-	select BR2_PACKAGE_BOOST
-	select BR2_PACKAGE_BOOST_REGEX
 	help
 	  Valijson is a header-only JSON Schema Validation library for
 	  C++. Valijson provides a simple validation API that allows
@@ -14,5 +10,5 @@ config BR2_PACKAGE_VALIJSON
 
 	  https://github.com/tristanpenman/valijson
 
-comment "valijson needs a toolchain w/ C++, threads, wchar  support"
-	depends on !BR2_INSTALL_LIBSTDCPP  || !BR2_TOOLCHAIN_HAS_THREADS || !BR2_USE_WCHAR
+comment "valijson needs a toolchain w/ C++"
+	depends on !BR2_INSTALL_LIBSTDCPP

package/valijson/valijson.mk

@@ -11,7 +11,6 @@ VALIJSON_LICENSE_FILES = LICENSE
 VALIJSON_CPE_ID_VENDOR = valijson_project
 VALIJSON_INSTALL_STAGING = YES
 VALIJSON_INSTALL_TARGET = NO
-VALIJSON_DEPENDENCIES = boost
 VALIJSON_CONF_OPTS = -Dvalijson_INSTALL_HEADERS=TRUE -Dvalijson_BUILD_TESTS=FALSE
 
 $(eval $(cmake-package))