add beginning of fedora nightly builds

docker_builds/fedora_40/Dockerfile

@@ -0,0 +1,4 @@
+FROM fedora:40
+ENV DEBIAN_FRONTEND=noninteractive 
+COPY do_build.sh /root
+RUN chmod +x /root/do_build.sh

docker_builds/fedora_40/do_build.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+set -e
+cd /root
+
+# Install dependencies and tools
+dnf update -y
+dnf install -y make gcc g++ cmake git wget p7zip fftw-devel glfw-devel volk-devel libzstd-devel codec2-devel airspyone_host-devel rtaudio-devel \
+            hackrf-devel rtl-sdr-devel portaudio-devel spdlog-devel libusbg-devel
+
+# Install SDRPlay libraries
+wget https://www.sdrplay.com/software/SDRplay_RSP_API-Linux-3.15.1.run
+7za x ./SDRplay_RSP_API-Linux-3.15.1.run
+7za x ./SDRplay_RSP_API-Linux-3.15.1
+cp x86_64/libsdrplay_api.so.3.15 /usr/lib/libsdrplay_api.so
+cp inc/* /usr/include/
+
+# Install librfnm
+git clone https://github.com/AlexandreRouma/librfnm
+cd librfnm
+mkdir build
+cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr
+make -j2
+make install
+cd ../../
+
+cd SDRPlusPlus
+mkdir build
+cd build
+cmake .. -DOPT_BUILD_AIRSPYHF_SOURCE=OFF -DOPT_BUILD_PLUTOSDR_SOURCE=OFF -DOPT_BUILD_RFNM_SOURCE=ON -DOPT_BUILD_SDRPLAY_SOURCE=ON -DOPT_BUILD_NEW_PORTAUDIO_SINK=ON -DOPT_BUILD_M17_DECODER=ON
+make VERBOSE=1 -j2