Don't use nproc on CI; it returns host threads

.circleci/config.yml

@@ -3,7 +3,7 @@ jobs:
   build:
     docker:
       - image: cimg/base:current-22.04
-    resource_class: large
+    resource_class: medium
     environment:
       - CACHE_DIR: ~/build/wxWidgets/staticlib
     steps:

.circleci/scripts/build_cubicsdr.sh

@@ -2,4 +2,4 @@
 mkdir -p $HOME/build/cjcliffe/CubicSDR-build
 cd $HOME/build/cjcliffe/CubicSDR-build
 cmake ~/project -DCMAKE_BUILD_TYPE=Release -DwxWidgets_CONFIG_EXECUTABLE=$HOME/build/wxWidgets/staticlib/bin/wx-config -DUSE_HAMLIB=1 -DENABLE_DIGITAL_LAB=1
-make -j$(nproc)
+make -j2

.circleci/scripts/build_liquiddsp.sh

@@ -10,5 +10,5 @@ echo "Configuring liquid-dsp.."
 ./configure > /dev/null
 
 echo "Building liquid-dsp.."
-make -j$(nproc) > /dev/null
+make -j2 > /dev/null
 sudo make install

.circleci/scripts/build_soapysdr.sh

@@ -8,6 +8,6 @@ cd $HOME/build/pothosware/SoapySDR-build
 cmake $HOME/build/pothosware/SoapySDR -DCMAKE_BUILD_TYPE=Release
 
 echo "Building SoapySDR.."
-make -j$(nproc) > /dev/null
+make -j2 > /dev/null
 
 sudo make install

.circleci/scripts/build_wxwidgets.sh

@@ -25,5 +25,5 @@ elif [ "$(uname)" == "Darwin" ]; then
 fi
 
 echo "Building wxWidgets.."
-make V=1 -j$(nproc)
+make V=1 -j2
 make install