[Buildroot] [git commit] json-for-modern-cpp: use $() to reference make variables instead of ${}

[Arnout Vandecappelle (Essensium/Mind)]

commit: https://git.buildroot.net/buildroot/commit/?id=de6968156cbc27526aa65b22d74fd9bf78342503
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

Signed-off-by: Ricardo Martincoski <ricardo.martincoski at gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be>
---
 package/json-for-modern-cpp/json-for-modern-cpp.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/json-for-modern-cpp/json-for-modern-cpp.mk b/package/json-for-modern-cpp/json-for-modern-cpp.mk
index 4bcfd46910..e547c07875 100644
--- a/package/json-for-modern-cpp/json-for-modern-cpp.mk
+++ b/package/json-for-modern-cpp/json-for-modern-cpp.mk
@@ -5,7 +5,7 @@
 ################################################################################
 
 JSON_FOR_MODERN_CPP_VERSION = v3.1.2
-JSON_FOR_MODERN_CPP_SOURCE = json-${JSON_FOR_MODERN_CPP_VERSION}.tar.gz
+JSON_FOR_MODERN_CPP_SOURCE = json-$(JSON_FOR_MODERN_CPP_VERSION).tar.gz
 JSON_FOR_MODERN_CPP_SITE = $(call github,nlohmann,json,$(JSON_FOR_MODERN_CPP_VERSION))
 JSON_FOR_MODERN_CPP_LICENSE = MIT
 JSON_FOR_MODERN_CPP_LICENSE_FILES = LICENSE.MIT