chore(ci): use nproc in MAKEFLAGS

- instead of hardcoding 4 CPU cores

ci/Jenkinsfile.android

@@ -63,6 +63,7 @@ pipeline {
     /* Control output the filename */
     APP_TYPE = "${utils.getAppType()}"
     PLATFORM = "android/arm64"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     QT_VERSION = "6.9.2"
     QT_ANDROID_PATH = "/opt/qt/${env.QT_VERSION}/android_arm64_v8a"
     QMAKE = "/opt/qt/${env.QT_VERSION}/android_arm64_v8a/bin/qmake"

ci/Jenkinsfile.ios

@@ -45,7 +45,7 @@ pipeline {
     GOTMPDIR = "${env.WORKSPACE_TMP}"
     PLATFORM = "ios/${getArch()}"
     /* Improve make performance */
-    MAKEFLAGS = "-j4 V=${params.VERBOSE}"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     QT_VERSION="6.9.2"
     QMAKE = "/Users/admin/${QT_VERSION}/ios/bin/qmake"
     QT_HOST_PATH = "/Users/admin/${QT_VERSION}/macos"

ci/Jenkinsfile.linux

@@ -76,7 +76,7 @@ pipeline {
   environment {
     PLATFORM = "linux/${getArch()}${(params.USE_NWAKU ?: false) ? '-nwaku' : ''}"
     /* Improve make performance */
-    MAKEFLAGS = "-j4 V=${params.VERBOSE}"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     /* Avoid weird bugs caused by stale cache. */
     QML_DISABLE_DISK_CACHE = "true"
     /* Set USE_NWAKU before VERSION since version.sh uses it */

ci/Jenkinsfile.linux-nix

@@ -59,7 +59,7 @@ pipeline {
   environment {
     PLATFORM = "linux-nix/${getArch()}"
     /* Improve make performance */
-    MAKEFLAGS = "-j4 V=${params.VERBOSE}"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     /* Avoid weird bugs caused by stale cache. */
     QML_DISABLE_DISK_CACHE = "true"
     /* Control output the filename */

ci/Jenkinsfile.macos

@@ -70,7 +70,7 @@ pipeline {
   environment {
     PLATFORM = "macos/${getArch()}${(params.USE_NWAKU ?: false) ? '-nwaku' : ''}"
     /* Improve make performance */
-    MAKEFLAGS = "-j4 V=${params.VERBOSE}"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     QT_VERSION="6.9.2"
     QMAKE = "/Users/admin/${QT_VERSION}/macos/bin/qmake"
     /* QMAKE = sh(script: "which qmake", returnStdout: true).trim() */

ci/Jenkinsfile.tests-ui

@@ -47,7 +47,7 @@ pipeline {
   environment {
     PLATFORM = 'tests/ui'
     /* Improve make performance */
-    MAKEFLAGS = "-j4 V=${params.VERBOSE}"
+    MAKEFLAGS = "-j${utils.getProcCount()} V=${params.VERBOSE}"
     /* Makefile assumes the compiler folder is included */
     QTDIR = "/opt/qt/6.9.2/gcc_64"
     PATH = "${env.QTDIR}/bin:${env.PATH}"