errors

lspci
03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:d723]
	Subsystem: Hewlett-Packard Company Device [103c:8319]

rfkill
0: hci0: Bluetooth
	Soft blocked: no
	Hard blocked: no

lshw
  *-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: enp2s0
       version: 15
       serial: 84:a9:3e:a0:6a:ab
       size: 10Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 duplex=half firmware=rtl8168h-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
       resources: irq:32 ioport:3000(size=256) memory:f0b04000-f0b04fff memory:f0b00000-f0b03fff
  *-network UNCLAIMED
       description: Network controller
       product: Realtek Semiconductor Co., Ltd.
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:03:00.0
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress cap_list
       configuration: latency=0
       resources: ioport:2000(size=256) memory:f0a00000-f0a0ffff

apt-get
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package build-essential is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'build-essential' has no installation candidate

./configure
loading cache ./config.cache
checking whether make sets ${MAKE}... no
checking for gcc... no
checking for cc... no
configure: error: no acceptable cc found in $PATH